Add more refinements to the keymap edit UI (#33847)

Quick follow-up to https://github.com/zed-industries/zed/pull/33816,
tidying it up some things a bit more.

Release Notes:

- N/A
2bf2c5c580Danilo Leal committed on 7/3/2025, 12:39:03 PM· committed by GitHubparenta6ee4a1
2 files changedLine totals unavailable