feat(heex): borrow matchit support from html (vim/vim#12717)
* feat(heex): borrow matchit support from html
Makes % support behave the same in heex as in html. For example, quickly moving the cursor between opening and closing tags.
* Remove unnecessary line; define b:undo_ftplugin first
* Remove b:html_set_match_words
8967f6c4b9
Co-authored-by: Chris Vincent <chris.vincent@hey.com>