Initial Perl support and some tests

[Leeft]

Checklist

• [ ] I have added tests
• [ ] I have updated the docs and cheatsheet
• [ ] I have not broken the cheatsheet

[pokey]

Btw you might consider using checkboxes in the issue description as your todo list, as that way it's easy for us to stay on the same page about what's left to do

[pokey]

Just wanted to check in to see where we were with this one; are we still waiting on stuff to be changed in tree-sitter-perl? Fwiw the new query-based approach to defining languages in Cursorless has now merged, so might make it easier to define some complex tree patterns if you want to leverage it. See the updated https://www.cursorless.org/docs/contributing/adding-a-new-language/#2-define-parse-tree-patterns-in-cursorless