Allow filter merge requests by comments
**Subject:**
Reviewing a lot of merge requests daily, i am write comments in some of them
After that i am cannot filter them back to review answers
**Suggestion:**
Add merge requests filter option to filter by comments, to work just like filter `My-Reaction=`
**Example**
`My-comment!=` to find where i am leave comment
`Comment-count!=` to find where some comments

issue