FR: Add the ability to search for filesets using jj op log

[zx8]

Is your feature request related to a problem? Please describe.

This started out as a discussion here, but it seems to not be possible at the moment without having to use --stat or --name-only and then inspect the operation log manually.

Describe the solution you'd like

I would like jj op log to be updated to accept an optional fileset to find operations which touched a particular (set of) file(s).

Describe alternatives you've considered

jj op log --stat and then ctrl-f to find operations manually.

[yuja]

This is discussed in e.g. #5316, but we'll probably want an opset language.