Remove filenames in tab-completion in fish >= 3.5

[pe]

Fish 3.5 did speed up loading custom fish completions. But also changed its behaviour in fish-shell/fish-shell@ff72e3f. It is now necessary to define at least one custom completion for 'git-fixup'. That pointed to an easier way: Write completions for 'git-fixup' and fish will forward them from 'git fixup' fish-shell/fish-shell@0916176

[keis]

Hey, thanks for the pull request!

Do you know if this script will work on earlier version of fish too? Or is it relying on some new features?

[pe]

I did not test it. But it should work with fish >= 3.2 released in March 2021. All Linux distributions I checked have fish >= 3.3.

People using older version of fish would only get completions for git-fixup but not git fixup.