[racket-dev] Pull request to use Racket lexer, and include in v5.3.2

> If you have any bug-fixes and changes that need to go in the release
> then make sure to specify that in the commit message or mail me the
> commit SHA1s.

Please see https://github.com/plt/racket/pull/211 (this is re Markdown
format render mode for Scribble):

    Use Racket lexer for code blocks

    Had been specifying Scheme lexer for code blocks, while waiting for
    new Racket lexer to wend its way from Pygments to Pygments.rb to
    Linguist to GitHub.

    That day is almost here: Linguist will soon update and deploy to
    GitHub. And Racket 5.3.2 is about to release. As a result, I think
    this is the correct time to switch to the Racket lexer: It should be
    live on GitHub by the time people are using Racket 5.3.2.

    /cc @rmculpepper -- I think this commit should go into the 5.3.2
    release.

Although the `@rmculpepper` in the commit message should have already
emailed you via GitHub, I'm posting this for belt+suspenders.