Feature/erlang mode

[ioolkos]

First version of an Erlang mode. Improvements are certainly possible and welcome. Currently configured for the Whatsapp ELP Erlang language server, but the Erlang LS could certainly be used as well.

[vindarel]

Great!

I left comments (I'm a helping hand).

Could you add a paragraph on the features this brings? Here, or on the package's :documentation, or in a new README… so that we can easily add doc to Lem's website.

I saw:

• syntax highlighting
• run Erlang
• send and eval region (async)
• LSP support (details?)
• REPL?

re style: I would define lists / property lists with the default (list :key val) instead of '(:key ,val) (and ,@).

[ioolkos]

@vindarel Thank you for your review & suggestions! I'll try to adapt & extend the PR, based on them.

[vindarel]

LGTM

cool, thanks. If the PR is ready you can add cxxxr as reviewer, I'll let him merge.

[cxxxr]

I think it's good and I merged. Thank you for the PR!