guides/versions: Use "snapshots" (instead of "versions") and "analyses"

The document already used the term "snapshot" a bit, and I think it's
less ambiguous/overloaded than "version" so use it consistently.
"Analyses" is already in use in other document and section titles, so
use that term in those contexts.

I didn't update the source document file names here, but maybe I should…

src/guides/versions.rst

@@ -1,6 +1,6 @@
-=================================
-Viewing previous versions of data
-=================================
+=========================
+Viewing previous analyses
+=========================
 
 
 .. contents:: Sections in this document
@@ -36,7 +36,7 @@ will load the dataset that was the latest available at that particular date.
 Tanglegrams to compare changes
 ------------------------------
 
-Using tanglegrams allows us to easily view two different versions of the same
+Using tanglegrams allows us to easily view two different snapshots of the same
 dataset side-by-side. Using the above examples we can view the latest dataset
 against the one from the middle of 2023 via the URL
 `flu/seasonal/h3n2/ha/6y:flu/seasonal/h3n2/ha/6y@2023-07-01
@@ -48,7 +48,7 @@ expansion of clade 2a.3a.1 over the past 6 months:
   :alt: Tanglegram of flu/seasonal/h3n2/ha/6y:flu/seasonal/h3n2/ha/6y@2023-07-01
 
 Over time, the data shown by this URL link will start to change as we update the
-latest version, but by versioning both datasets we can preserve this exact view
+latest snapshot, but by dating both datasets we can preserve this exact view
 into the data:
 `flu/seasonal/h3n2/ha/6y@2024-01-03:flu/seasonal/h3n2/ha/6y@2023-07-01
 <https://nextstrain.org/flu/seasonal/h3n2/ha/6y@2024-01-03:flu/seasonal/h3n2/ha/6y@2023-07-01>`__.
@@ -57,7 +57,7 @@ into the data:
 SARS-CoV-2 datestamped datasets
 -------------------------------
 
-Prior to the functionality described here we exposed dated versions of some of
+Prior to the functionality described here we exposed dated snapshots of some of
 our datasets by including the YYYY-MM-DD in the URL without the ``@`` character,
 i.e. the date string was part of the dataset name. This functionality is now
 superseded by the new URL syntax described here, and we may stop producing these
@@ -117,7 +117,7 @@ to the latter. The result of this is that the earliest available
 ``dengue/denv1/genome`` dataset is from 2024-01-03, despite DENV1 datasets being
 available since January 2019.
 
-We have plans to expose these versions - see `this issue
+We have plans to expose these snapshots - see `this issue
 <https://github.com/nextstrain/nextstrain.org/issues/777>`__ for progress here.
 
 
@@ -139,6 +139,6 @@ meta+tree JSONs in the case of v1 datasets).
 How far back does this go?
 --------------------------
 
-The oldest versioned dataset `is a H3N2 dataset from August 2018
+The oldest dataset snapshot `is a H3N2 dataset from August 2018
 <https://nextstrain.org/flu/seasonal/h3n2/ha/3y@2018-08-01>`__. While Nextstrain
 datasets existed before then, we didn't have versioning enabled.

src/index.rst

@@ -68,7 +68,7 @@ team and other Nextstrain users provide assistance.  For private inquiries,
     Bioinformatics <guides/bioinformatics/index>
     Sharing analyses <guides/share/index>
     Communicating scientific insights <guides/communicate/index>
-    Viewing previous versions <guides/versions>
+    Viewing previous analyses <guides/versions>
     Managing an installation <guides/manage-installation>
     Contributing <guides/contribute/index>
 

src/learn/about.rst

@@ -25,8 +25,8 @@ snapshots of evolving pathogen populations such as `SARS-CoV-2
 We use interactive visualizations to enable exploration of curated datasets and
 analyses which are continually updated when new genomes are available.  This
 offers a powerful pathogen surveillance tool to virologists, epidemiologists,
-public health officials, and community scientists. In many cases old versions of
-these analyses are able to be easily accessed, see :doc:`viewing previous versions
+public health officials, and community scientists. In many cases old snapshots of
+these analyses are able to be easily accessed, see :doc:`viewing previous analyses
 </guides/versions>` for more.
 
 .. rubric:: Open-source software