[css-grid-3][editorial] Rename masonry axis to stacking axis

Because a masonry layout is composed of both a grid axis and a stacking axis.

css-grid-3/Overview.bs

@@ -159,7 +159,7 @@ Masonry Layout Model</h2>
 	lays out items into pre-defined tracks similar to [=grid layout=] in one axis
 	(called the <dfn local-lt="grid-axis">grid axis</dfn>),
 	but flows them freely similar to [=flex layout=] in the other
-	(called the <dfn local-lt="masonry-axis">masonry axis</dfn>).
+	(called the <dfn local-lt="stacking-axis">stacking axis</dfn>).
 	Similar to [=grid layout=] and unlike [=flex layout=],
 	[=masonry layout=]’s auto-placement
 	distributes items across the tracks  to keep the lengths of those tracks
@@ -178,9 +178,9 @@ Masonry Layout Model</h2>
 
 	A <dfn>masonry container</dfn> is a box whose contents participate in [=masonry layout=].
 	A [=masonry container=] is a <dfn export>column masonry container</dfn>
-	if its [=masonry axis=] is the [=block axis=],
+	if its [=stacking axis=] is the [=block axis=],
 	or a <dfn export>row masonry container</dfn>
-	if its [=masonry axis=] is the [=inline axis=].
+	if its [=stacking axis=] is the [=inline axis=].
 
 	<table class=data>
 		<caption>Establishing Masonry Containers</caption>
@@ -237,7 +237,7 @@ Masonry Layout Model</h2>
 <span class="option grid">Grid-integrated Option:</span> Establishing Masonry Layout</h3>
 
 <h4 id="grid-template-masonry">
-Indicating the Masonry Axis: the ''grid-template-columns/masonry'' keyword for 'grid-template-columns'/'grid-template-rows'</h3>
+Indicating the stacking axis: the ''grid-template-columns/masonry'' keyword for 'grid-template-columns'/'grid-template-rows'</h3>
 
 	<pre class='propdef partial'>
 		Name: grid-template-columns, grid-template-rows
@@ -252,7 +252,7 @@ Indicating the Masonry Axis: the ''grid-template-columns/masonry'' keyword for '
 
 	[=Masonry layout=] can be applied to [=grid containers=]
 	by specifying the value ''grid-template-columns/masonry'' for one of its axes,
-	defining it as the [=masonry axis=].
+	defining it as the [=stacking axis=].
 	Such [=grid containers=] are called [=masonry containers=].
 
 	If ''grid-template-columns/masonry'' is specified
@@ -334,28 +334,28 @@ Masonry Track Direction: the 'masonry-direction' property</h4>
 	The 'masonry-direction' property
 	specifies how items are placed
 	in the [=masonry container=],
-	by setting its [=masonry axis=] and direction.
+	by setting its [=stacking axis=] and direction.
 
 	<dl dfn-type=value dfn-for=masonry-direction>
 		: <dfn>column</dfn>
-		:: The [=masonry container's=] [=masonry axis=] is its [=block axis=],
+		:: The [=masonry container's=] [=stacking axis=] is its [=block axis=],
 			and masonry layout starts from its [=block-start=] edge.
 
 		: <dfn>column-reverse</dfn>
-		:: The [=masonry container's=] [=masonry axis=] is its [=block axis=],
+		:: The [=masonry container's=] [=stacking axis=] is its [=block axis=],
 			and masonry layout starts from its [=block-end=] edge.
 
 		: <dfn>row</dfn>
-		:: The [=masonry container's=] [=masonry axis=] is its [=inline axis=],
+		:: The [=masonry container's=] [=stacking axis=] is its [=inline axis=],
 			and masonry layout starts from its [=inline-start=] edge.
 
 		: <dfn>row-reverse</dfn>
-		:: The [=masonry container's=] [=masonry axis=] is its [=inline axis=],
+		:: The [=masonry container's=] [=stacking axis=] is its [=inline axis=],
 			and masonry layout starts from its [=inline-end=] edge.
 	</dl>
 
 	The [=masonry container's=] [=grid axis=]
-	is perpendicular to its [=masonry axis=].
+	is perpendicular to its [=stacking axis=].
 
 
 <h4 id=masonry-fill>
@@ -516,7 +516,7 @@ Subgrids</h3>
 	If the parent's corresponding axis is a [=grid axis=],
 	the subgridded axis is taken from the parent container
 	[[css-grid-2#subgrids|as specified for grid containers]];
-	if the parent's corresponding axis is a [=masonry axis=]...
+	if the parent's corresponding axis is a [=stacking axis=]...
 
 	<section class="option grid">
 	<span class="option grid">Grid-integrated Syntax:</span>
@@ -594,7 +594,7 @@ Subgrids</h3>
 		to the intrinsic size of the 2nd row in the parent grid.
 		This is possible since the subgrid specified a definite position
 		so we know which tracks it will occupy.
-		Note also that trying to subgrid the parent's [=masonry axis=]
+		Note also that trying to subgrid the parent's [=stacking axis=]
 		results in the subgrid getting [=masonry layout=] in its [=inline axis=].
 	</div>
 
@@ -909,7 +909,7 @@ Containing Block</h2>
 
 	The [=containing block=] for a [=grid item=] participating in [=masonry layout=]
 	is formed by its [=grid area=] in the [=grid axis=]
-	and the [=grid container=]'s [=content box=] in the [=masonry axis=].
+	and the [=grid container=]'s [=content box=] in the [=stacking axis=].
 
 <h4 id="rtl-example">
 Placement and Writing Modes</h4>
@@ -918,7 +918,7 @@ Placement and Writing Modes</h4>
 	masonry layout and placement is sensitive to the [=writing mode=].
 	For example, for ''direction: rtl'',
 	items are placed right-to-left rather than left-to-right,
-	whether the inline axis is a [=grid axis=] or a [=masonry axis=].
+	whether the inline axis is a [=grid axis=] or a [=stacking axis=].
 
 	<div class="example">
 		Here's a simple <a href="examples/rtl-grid-axis.html">example</a> using ''direction: rtl'' in the [=grid axis=]:
@@ -956,7 +956,7 @@ Placement and Writing Modes</h4>
 
 	<div class="example">
 		Here's a simple <a href="examples/rtl-masonry-axis.html">example</a>
-		using ''direction: rtl'' in the [=masonry axis=]:
+		using ''direction: rtl'' in the [=stacking axis=]:
 
 		```css
 			<style>
@@ -995,8 +995,8 @@ Placement and Writing Modes</h4>
 Sizing Grid Containers</h2>
 
 	[[css-grid-2#intrinsic-sizes|Sizing Grid Containers]] works the same as for regular [=grid containers=]
-	but with the following addendum for the [=masonry axis=]:
-	The <a>max-content size</a> (<a>min-content size</a>) of a [=grid container=] in the [=masonry axis=]
+	but with the following addendum for the [=stacking axis=]:
+	The <a>max-content size</a> (<a>min-content size</a>) of a [=grid container=] in the [=stacking axis=]
 	is the largest distance between the [=grid container's=] [=content-box=] [=start=] edge
 	and the maximum [=margin-box=] end of all the items,
 	when sized under a <a>max-content constraint</a> (<a>min-content constraint</a>).
@@ -1039,15 +1039,15 @@ Sizing Grid Containers</h2>
 Alignment and Spacing</h2>
 
 	[[css-grid-2#gutters|Gutters]] are supported in both axes.
-	In the [=masonry axis=],
+	In the [=stacking axis=],
 	the gap is applied between the margin boxes of each pair of adjacent items.
 	Margins do not collapse in either axis.
 
 	In the [=grid axis=],
 	[[css-grid-2#alignment|alignment]]
 	works the same as in a regular [=grid container=].
 
-	In the [=masonry axis=],
+	In the [=stacking axis=],
 	[[css-align-3#content-distribution|content-distribution]] is applied
 	to the content as a whole, similarly to how it behaves in block containers.
 	More specifically, the <a>alignment subject</a> is the <dfn>masonry box</dfn>,
@@ -1063,7 +1063,7 @@ Alignment and Spacing</h2>
 	</figure>
 
 	Note: There is only ever one <a>alignment subject</a>
-	for these properties in the [=masonry axis=],
+	for these properties in the [=stacking axis=],
 	so the unique 'align-content' / 'justify-content' values boil down to
 	''align-content/start'',
 	''align-content/center'',
@@ -1073,21 +1073,21 @@ Alignment and Spacing</h2>
 	is identical to ''align-content/start'',
 	and the [=distributed alignment=] values behave as their [=fallback alignments=].)
 	If the [=grid items=] overflow
-	the [=grid container=]'s [=content box=] in the [=masonry axis=],
+	the [=grid container=]'s [=content box=] in the [=stacking axis=],
 	then the [=masonry box=] will be larger than the [=grid container=]'s [=content box=].
 
-	ISSUE: Should alignment in the masonry axis do something more sophisticated?
+	ISSUE: Should alignment in the stacking axis do something more sophisticated?
 	What should that be?
 
 <h3 id="masonry-axis-baseline-alignment">
-Baseline Alignment in the Masonry Axis</h3>
+Baseline Alignment in the stacking axis</h3>
 
 	Item [=baseline alignment=] inside the [=grid axis=] tracks
 	works as usual for a regular [=grid container=],
 	and the [=grid container=]'s baseline is determined
 	the same as for a regular [=grid container=] in that axis.
 
-	[=Baseline alignment=] is not supported in the [=masonry axis=].
+	[=Baseline alignment=] is not supported in the [=stacking axis=].
 	The first baseline set of the [=grid container=] in this axis
 	is generated from the [=alignment baseline=] of
 	the first [=grid item=] in the first occupied track,
@@ -1101,9 +1101,9 @@ Baseline Alignment in the Masonry Axis</h3>
 Fragmentation</h2>
 
 <h3 id="masonry-axis-pagination">
-Fragmentation in the Masonry Axis</h3>
+Fragmentation in the stacking axis</h3>
 
-	Each [=grid axis=] track is fragmented independently in the [=masonry axis=].
+	Each [=grid axis=] track is fragmented independently in the [=stacking axis=].
 	If a [=grid item=] is fragmented,
 	or has a [=forced break=] before/after it,
 	then the [=running position=] for the tracks that it spans in the [=grid axis=]
@@ -1155,12 +1155,12 @@ Absolute Positioning</h2>
 
 	[[css-grid-1#abspos-items|Grid-aligned absolute-positioned descendants]] are supported
 	in [=masonry containers=] just as for regular [=grid containers=];
-	however, in the [=masonry axis=] there exist only two lines (in addition to the ''grid-area/auto'' lines) for placement:
+	however, in the [=stacking axis=] there exist only two lines (in addition to the ''grid-area/auto'' lines) for placement:
 
 	* line 1 (line -2) corresponds to the start edge of the [=masonry box=]
 	* line 2 (line -1) corresponds to the end edge of the [=masonry box=]
 
-	ISSUE: It might be useful to define a static position in the [=masonry axis=].
+	ISSUE: It might be useful to define a static position in the [=stacking axis=].
 	Maybe it could defined as the max (or min?) current [=running position=]
 	of the [=grid-axis=] tracks at that point?  Or the end of the item before it?
 
@@ -1169,7 +1169,7 @@ Performance Notes</h2>
 
 	In general, masonry layout should have significantly better performance
 	than the equivalent regular (2-axis) grid layout,
-	particularly when the [=masonry axis=] is the [=block axis=]
+	particularly when the [=stacking axis=] is the [=block axis=]
 	since the intrinsic sizing of grid rows is typically quite expensive.
 	Any intrinsic track sizing in the [=grid axis=] should be cheaper too,
 	because, typically, only a subset of items contribute to the intrinsic sizing in a masonry layout,
@@ -1184,7 +1184,7 @@ Performance Notes</h2>
 	by opting out from the stretching on most items though,
 	e.g. specifying ''justify/align-items:start''
 	and then opting in for just a few items with ''justify/align-self:stretch''
-	to let those items fill the [=masonry axis=].
+	to let those items fill the [=stacking axis=].
 	(This performance analysis is from a Gecko perspective,
 	but I suspect there's some truth to it for other layout engines as well.)