Feature add - Find match count (issue #4805)

Hi all!

This is my first contribution to the project (and first time looking at this codebase)–so I apologize ahead of time if I have missed anything obvious. What I've done here is try to implement a simple match count for the find bar.

Please let me know if there's something I have misplaced or just done wrong. I'm open to feedback and look forward to contributing more to this project.