Add additional keywords for Elixir

[ben-dyer]

Add defmacro, quote and unquote keywords for elixir (cf. https://hexdocs.pm/elixir/1.12/syntax-reference.html#the-elixir-ast) and also added defn for numerical definition (https://github.com/elixir-nx/nx/tree/main/nx#numerical-definitions)

[github-actions]

JS File Size Changes (gzipped)

A total of 1 files have changed, with a combined diff of +13 B (+1.5%).

file	master	pull	size diff	% diff
components/prism-elixir.min.js	844 B	857 B	+13 B	+1.5%

Generated by 🚫 dangerJS against 275542d

[RunDevelopment]

Thank you for the PR @ben-dyer!

Please add the new keywords to Elixir's keyword test (more info).

Also, we commit the minified files as well. Please run npm ci && npm run build and commit the changes.

[ben-dyer]

@RunDevelopment Thanks for the help 🙇

[RunDevelopment]

Nice.

Thank you for contributing @ben-dyer!