fix(elixir): separate function from parameter matching

[skbolton]

Previous queries were mixing the parameter matches and the function matches into the same query. This would make it so that functions that didn't have parameters wouldn't match @function.inner or @function.outer queries.

Separating them makes it easier to focus on the specifics of fulfilling each query. This should resolve issue nvim-treesitter#249.

[skbolton]

Sorry @kiyoon for the barage of PR's I was trying to break up my work into smaller pieces. I wasn't sure all who is involved in this project and how many eyes would see it.

[kiyoon]

When I test it, it seems to be not working with functions with parameters in #249 examples?

[kiyoon]

Thanks a lot for your work, and no worries, it makes it easier to focus on one problem at a time.

[skbolton]

Thanks for the reminder on this PR @yihuikhuu. I'll take another stab at this incorporating your feedback this week.

[calops]

I should have checked existing PRs before opening #605 😅

Mine seems to be a lot simpler, but maybe it's too generic? I've tested it a bit and it seems to match all call parameters in every situation (and it helps simplify other queries as well) without breaking other stuff, but maybe I'm missing something.