Support Elixir for Snippets

Elixir support for Bitbucket has been around for a few years (see issues BCLOUD-3848 and BCLOUD-7852) which is great!

However, one thing that seems to be missing still, is support for Elixir syntax highlighting in Snippets. The ".ex" extension defaults to "Eiffel" instead and Elixir doesn’t show up in the language dropdown.

It would be really cool and I’d find it tremendously useful if you could add Elixir support to Snippets