Add browser support policy for Scribble-generated documentation.

[samth]

The short summary: all evergreen browsers from the past year, plus anything <5 years old with at least 1% share on docs.racket-lang.org.

Rendered

[sorawee]

I think the requirement to have a minimal support for IE6 doesn't make much sense. IE6 by default can't even view sites with https protocol. Even when TLS1.0 is manually enabled, racket-lang.org (and most websites in the world) seems to be serving a content that IE6 doesn't understand, so it will fail with "The page cannot be displayed". This means that users who are still using it can't download Racket in the first place, so there's really no point to support it.

[sorawee]

FYI: if anyone wants to test IE (including IE6), you can use VMs provided by Microsoft. Unfortunately, Microsoft took these VMs down from their website for unknown reasons, but some users archived them. Use them at your own risk.

• https://gist.github.com/zmwangx/e728c56f428bc703c6f6#gistcomment-3196040
• https://gist.github.com/zmwangx/e728c56f428bc703c6f6#gistcomment-3115797

As noted above, for IE6, we need to enable TLS1.0 to access https websites, but racket-lang.org can't be accessed regardless.

[LiberalArtist]

FWIW, while I don't care about IE6, I do use lynx from time to time, and the docs are quite readable in it.