Pull-requests: I need to Search among the pull-request comments.

I'm reviewing a code. I want to refer a person to one of my comments in one of my multiple previous code reviews (pull-requests). I open the page of my pull-requests, the page's URL looks about like this: https://<domain>/<path>/pull-requests?state=MERGED (Filter by: "Merged", "I'm reviewing").

In the top-right corner of that page there is a Search text box. If I enter there a key phrase from one of my previous pull-request comments then it shows the search results of some other area (which I don't need) while I need it to show the search results among my comments to the previous pull-requests.

How to get that functionality? The more pull-requests I review the more and more time it takes me to find what I need.