feat(pack): add elixir lang pack with `expert` #1743

3 / 8 tasks completed

5 tasks still to be completed

Task	Status
Adds `elixir`, `heex`, and `eex` Treesitter parsers	Completed
Adds Expert LSP via Mason (`mason-tool-installer`)	Completed
Adds `mix format` formatter via `conform.nvim`	Completed
Pull request title has the appropriate conventional commit type and scope where the scope is the name of the pre-existing directory in the project as described above	Incomplete
`README` is properly formatted and uses fenced in links with `<url>` unless they are inside a `[title](url)`	Incomplete
Entry returns a single plugin spec with the new plugin as the only top level spec (not applicable for recipes or packs).	Incomplete
Proper usage of `opts` table rather than setting things up with the `config` function.	Incomplete
Proper usage of `specs` table for all specs that are not dependencies of a given plugin (not applicable for recipes or packs).	Incomplete