Right now we're using the 'content' role as default which will just render
these things as cursive (which isn't really useful for code examples). It also
prevents us from assigning a more useful default role in the future.
The page describing how to get the sources was more about contributing
to LLDB than getting the actual source. This patch moves some things
around and repurposes this page as a contributing to LLDB landing page.
Kazu Hirata