[feature] Shell completion #5104
Description
Describe the issue
How about add bash/zsh/fish/posh/etc completion? Just like other git subcommands?
❯ git add --<TAB>
option
--all add, modify, and remove index entries to match the working tree
--chmod override the executable bit of the listed files
--dry-run do not actually add files; only show which ones would be added
--edit open diff against index in editor
--force allow adding otherwise ignored files
--ignore-errors continue adding if an error occurs
--ignore-removal like "--all" but ignore removals
--intent-to-add record only that path will be added later
...
A test example:
❯ compdef '_arguments -S -s "*: :((checkout\:'\''Populate working copy with real content from Git LFS files.'\'' dedup\:'\''De-duplicate Git LFS files.'\''))"' git-lfs
_arguments -S -s "*: :((checkout\:'Populate working copy with real content from Git LFS files.' dedup\:'De-duplicate Git LFS files.'))" git-lfs
❯ git-lfs <TAB>
checkout Populate working copy with real content from Git LFS files.
dedup De-duplicate Git LFS files.
I guess https://jmtirado.net/shell-completion-with-cobra-and-go/ and https://github.com/cli/cli/blob/cf4b73ff958b272cf3c9c0cf9351459f76b793a0/pkg/cmd/completion/completion.go may be helpful?
Thanks.