README: move "Binary Installation" up and tidy it (JuliaLang#31912)

Since this is how the vast majority of people will want to install Julia, it seems sensible to have it near the top of the page. This section had some very weird formatting in terms of whitespace, so I tidied that up while I was at it.

README.md

@@ -48,6 +48,22 @@ helpful to start contributing to the Julia codebase.
 - [**Twitter**](https://twitter.com/JuliaLanguage)
 - [**Meetup**](https://julia.meetup.com/)
 
+## Binary Installation
+
+If you would rather not compile the latest Julia from source,
+platform-specific tarballs with pre-compiled binaries are also
+[available for download](https://julialang.org/downloads/).
+
+If everything works correctly, you will see a Julia banner and an
+interactive prompt into which you can enter expressions for
+evaluation.  You can read about [getting
+started](https://julialang.org/manual/getting-started) in the manual.
+
+**Note**: Although some system package managers provide Julia, such
+installations are neither maintained nor endorsed by the Julia
+project. They may be outdated, broken and/or unmaintained. We
+recommend you use the official Julia binaries instead.
+
 ## Currently Supported Platforms
 
 | Operating System | Architecture     | CI | Binaries | Support Level |
@@ -132,22 +148,6 @@ into. Julia can be completely uninstalled by deleting this
 directory. Julia packages are installed in `~/.julia` by default, and
 can be uninstalled by deleting `~/.julia`.
 
-## Binary Installation
-
-If  you  would  rather  not  compile the  latest  Julia  from  source,
-platform-specific  tarballs   with  pre-compiled  binaries   are  also
-[available for download](https://julialang.org/downloads/).
-
-If everything works correctly, you will see a Julia banner and an
-interactive prompt into which you can enter expressions for
-evaluation.  You can read about [getting
-started](https://julialang.org/manual/getting-started) in the manual.
-
-**Note**: Although some system package managers provide Julia, such
-installations are neither maintained nor endorsed by the Julia
-project. They may be outdated and/or unmaintained. We recommend you
-use the official Julia binaries instead.
-
 ## Source Code Organization
 
 The Julia source code is organized as follows: