Swap order of single-file/full-install sections

docs/install.md

@@ -78,113 +78,6 @@ Here's an overview of the tradeoffs involved.
 
 Here are the instructions for each installation method we support.
 
-### Single file {#single-file}
-
-The Au library can be packaged as a single header file, which you can include in your project just
-like any other header.  This works with any build system!
-
-To take this approach, obtain the single file by one of the methods described below.  Then, put it
-inside a `third_party` folder (for example, as `third_party/au.hh`).  Now you're up and running with
-Au!
-
-Every single-file package automatically includes the following features:
-
-- Basic "unit container" types: [`Quantity`](./reference/quantity.md),
-  [`QuantityPoint`](./reference/quantity_point.md)
-- [Magnitude](./reference/magnitude.md) types and values, including constants for any integer such
-  as `mag<5280>()`.
-- All [prefixes](./reference/prefix.md) for SI (`kilo`, `mega`, ...) and informational (`kibi`,
-  `mebi`, ...) quantities.
-- [Math functions](./reference/math.md), including unit-aware rounding and inverses, trigonometric
-  functions, square roots, and so on.
-- _Bidirectional implicit conversion_ between `Quantity` types and any [equivalent counterparts in the
-  `std::chrono` library](./reference/corresponding_quantity.md#chrono-duration).
-
-Here are the two ways to get a single-file packaging of the library.
-
-#### Pre-built single file
-
-!!! tip
-    This approach is mainly for _playing_ with the library.  It's very fast to get up and running,
-    but it's not the best choice as the "production" installation of your library.
-
-    For a single-file approach, most users will be much better served by the next section, which
-    explains how to customize it to get exactly the units you want.
-
-We provide pre-generated single-file versions of the library, automatically generated from the
-latest commit in the repo:
-
-- [`au.hh`](./au.hh)
-- [`au_noio.hh`](./au_noio.hh)
-  (Same as above, but with `<iostream>` support stripped out)
-
-These include very few units (to keep compile times short).  However, _combinations_ of these units
-should get you any other unit you're likely to want.  The units we include are:
-
-- Every SI base unit (`seconds`, `meters`, `kilo(grams)`, `amperes`, `kelvins`, `moles`, `candelas`)
-- Base units for angles and information (`radians`, `bits`)
-- A base dimensionless unit (`unos`)
-
-!!! note
-    _How_ do you go about constructing other units from these?  By **composing** them.  For example,
-    you can make [other coherent SI units](https://www.nist.gov/pml/owm/metric-si/si-units) like
-    this:
-
-    ```cpp
-    constexpr auto newtons = kilo(gram) * meters / squared(second);
-    ```
-
-    Now you can call, say, `newtons(10)` and get a quantity equivalent to 10 Newtons.  You can also
-    **scale** a unit by multiplying by Magnitude objects.  For example:
-
-    ```cpp
-    constexpr auto degrees = radians * Magnitude<Pi>{} / mag<180>();
-    ```
-
-    These will "work", in the sense of producing correct results.  But these ad hoc unit definitions
-    are far less usable than [fully defined units](./howto/new-units.md).  Both the type names and
-    the unit symbols will be needlessly complicated.
-
-    Again, we recommend following the directions in the next section to get _exactly_ the units you
-    care about.
-
-??? warning "Pre-built files with all units"
-    We also provide pre-built files with every unit the library knows about.
-
-    We don't advertise this option widely, because the library's compile time slowdown is largely
-    proportional to the number of units included in a translation unit.  Thus, not only will this
-    configuration be the slowest of all, but _it will get increasingly slower as the library gets
-    better over time_ (by supporting more and more units out of the box).
-
-    Therefore, these files are only for use cases where _you don't care about compile time_.  The
-    primary example is [the Compiler Explorer ("godbolt")](https://godbolt.org/z/KrvfhP4M3).
-
-    **If you don't care about compile times**, here are the files:
-
-    - [`au_all_units.hh`](./au_all_units.hh)
-    - [`au_all_units_noio.hh`](./au_all_units_noio.hh)
-      (Same as above, but with `<iostream>` support stripped out)
-
-
-#### Custom single file
-
-It's easy to package the library in a _custom_ single file with _exactly_ the units you need.
-Here's how:
-
-1. **Clone the repo**.  Go to the [aurora-opensource/au](https://github.com/aurora-opensource/au)
-   repo, and follow the typical instructions.
-    - If you're just a _user_ of Au, not a _contributor_, this should be:<br>
-      `git clone https://github.com/aurora-opensource/au.git`
-
-2. **Run the script**.  `tools/bin/make-single-file --units meters seconds newtons > ~/au.hh`
-   creates a file, `~/au.hh`, which packages the entire library in a single file with these three
-   units.
-    - To see the full list of available units, search the `.hh` files in the `au/units/` folder. For
-      example, `meters` will include the contents of `au/units/meters.hh`.
-    - Provide the `--noio` flag if you prefer to avoid the expense of the `<iostream>` library.
-
-Now you have a file, `~/au.hh`, which you can add to your `third_party` folder.
-
 ### Full library installation {#full}
 
 #### bazel
@@ -340,3 +233,110 @@ Each package manager contains setup instructions on its page for Au.  Here are t
 
 - **Conan:** [au](https://conan.io/center/recipes/au)
 - **vcpkg:** [aurora-au](https://vcpkg.link/ports/aurora-au)
+
+### Single file {#single-file}
+
+The Au library can be packaged as a single header file, which you can include in your project just
+like any other header.  This works with any build system!
+
+To take this approach, obtain the single file by one of the methods described below.  Then, put it
+inside a `third_party` folder (for example, as `third_party/au.hh`).  Now you're up and running with
+Au!
+
+Every single-file package automatically includes the following features:
+
+- Basic "unit container" types: [`Quantity`](./reference/quantity.md),
+  [`QuantityPoint`](./reference/quantity_point.md)
+- [Magnitude](./reference/magnitude.md) types and values, including constants for any integer such
+  as `mag<5280>()`.
+- All [prefixes](./reference/prefix.md) for SI (`kilo`, `mega`, ...) and informational (`kibi`,
+  `mebi`, ...) quantities.
+- [Math functions](./reference/math.md), including unit-aware rounding and inverses, trigonometric
+  functions, square roots, and so on.
+- _Bidirectional implicit conversion_ between `Quantity` types and any [equivalent counterparts in the
+  `std::chrono` library](./reference/corresponding_quantity.md#chrono-duration).
+
+Here are the two ways to get a single-file packaging of the library.
+
+#### Pre-built single file
+
+!!! tip
+    This approach is mainly for _playing_ with the library.  It's very fast to get up and running,
+    but it's not the best choice as the "production" installation of your library.
+
+    For a single-file approach, most users will be much better served by the next section, which
+    explains how to customize it to get exactly the units you want.
+
+We provide pre-generated single-file versions of the library, automatically generated from the
+latest commit in the repo:
+
+- [`au.hh`](./au.hh)
+- [`au_noio.hh`](./au_noio.hh)
+  (Same as above, but with `<iostream>` support stripped out)
+
+These include very few units (to keep compile times short).  However, _combinations_ of these units
+should get you any other unit you're likely to want.  The units we include are:
+
+- Every SI base unit (`seconds`, `meters`, `kilo(grams)`, `amperes`, `kelvins`, `moles`, `candelas`)
+- Base units for angles and information (`radians`, `bits`)
+- A base dimensionless unit (`unos`)
+
+!!! note
+    _How_ do you go about constructing other units from these?  By **composing** them.  For example,
+    you can make [other coherent SI units](https://www.nist.gov/pml/owm/metric-si/si-units) like
+    this:
+
+    ```cpp
+    constexpr auto newtons = kilo(gram) * meters / squared(second);
+    ```
+
+    Now you can call, say, `newtons(10)` and get a quantity equivalent to 10 Newtons.  You can also
+    **scale** a unit by multiplying by Magnitude objects.  For example:
+
+    ```cpp
+    constexpr auto degrees = radians * Magnitude<Pi>{} / mag<180>();
+    ```
+
+    These will "work", in the sense of producing correct results.  But these ad hoc unit definitions
+    are far less usable than [fully defined units](./howto/new-units.md).  Both the type names and
+    the unit symbols will be needlessly complicated.
+
+    Again, we recommend following the directions in the next section to get _exactly_ the units you
+    care about.
+
+??? warning "Pre-built files with all units"
+    We also provide pre-built files with every unit the library knows about.
+
+    We don't advertise this option widely, because the library's compile time slowdown is largely
+    proportional to the number of units included in a translation unit.  Thus, not only will this
+    configuration be the slowest of all, but _it will get increasingly slower as the library gets
+    better over time_ (by supporting more and more units out of the box).
+
+    Therefore, these files are only for use cases where _you don't care about compile time_.  The
+    primary example is [the Compiler Explorer ("godbolt")](https://godbolt.org/z/KrvfhP4M3).
+
+    **If you don't care about compile times**, here are the files:
+
+    - [`au_all_units.hh`](./au_all_units.hh)
+    - [`au_all_units_noio.hh`](./au_all_units_noio.hh)
+      (Same as above, but with `<iostream>` support stripped out)
+
+
+#### Custom single file
+
+It's easy to package the library in a _custom_ single file with _exactly_ the units you need.
+Here's how:
+
+1. **Clone the repo**.  Go to the [aurora-opensource/au](https://github.com/aurora-opensource/au)
+   repo, and follow the typical instructions.
+    - If you're just a _user_ of Au, not a _contributor_, this should be:<br>
+      `git clone https://github.com/aurora-opensource/au.git`
+
+2. **Run the script**.  `tools/bin/make-single-file --units meters seconds newtons > ~/au.hh`
+   creates a file, `~/au.hh`, which packages the entire library in a single file with these three
+   units.
+    - To see the full list of available units, search the `.hh` files in the `au/units/` folder. For
+      example, `meters` will include the contents of `au/units/meters.hh`.
+    - Provide the `--noio` flag if you prefer to avoid the expense of the `<iostream>` library.
+
+Now you have a file, `~/au.hh`, which you can add to your `third_party` folder.