Describe the feature or problem you’d like to solve

I use the gh CLI to open PRs for review by coworkers. I like the feature where you can add reviewers from the CLI. I work with some coworkers whose names have diacritics, e.g. Miķelis, Klāvs, Dāvis.

When I try and search for their name in the CLI, I will type something like:

? Reviewers Mi  [Use arrows to move, space to select, <right> to all, <left> to none, type to filter]
> [ ]  testuser (Miķelis Test)

When I then type k, the person's name disappears from the list:

? Reviewers Mik  [Use arrows to move, space to select, <right> to all, <left> to none, type to filter]

Proposed solution

Allow searching for names with diacritics using "regular" characters. This will help users who have names that aren't "regular" names. I would expect when I type mik, this would match a user named Miķelis.