[Pages] Add additional language support

[neynah]

@1000hz noticed that the section on Language support and tools Language support and tools is missing some languages. From what I can tell it looks like we're missing Go, Swift, and Rust.

cc @signalnerve

[kristianfreeman]

Closing this from #848. Rust and Swift aren't installed by default, so I've added a new ticket to document that and how to install them: #849