Fish autocomplete doesn't work with `inv` command

[Techcable]

Two things need to be done to fix this.

In order for fish to recognize inv as a supported command, pass ---comand inv to complete in addition to --comand invoke.

invoke/invoke/completion/fish.completion

Line 10 in 2a8f95f

complete --command {binary} --no-files --arguments '(__complete_{binary})'

Additionally, for completion autoloading to work, the inv.fish file needs to be system linked to invoke.fish.

I would contribute a fix, but it looks like you use {binary} instead of hard-coding invoke. The built-in template logic has no way to expand ["inv", "invoke"] to "--command invoke --comand inv". The second issue with a fix is that I don't know to install inv.fish alongside invoke.fish.

Are you okay with hardcoding --command inv in the completion file, and how would I modify the logic for installing completions?