Missing completion on git aliasses

[jorritsmit]

For now i only found missing completion on gco of the branch names. when i type git checkout the branch names are auto-completed, but not using gco. I found how to enable that in this stackoverflow question: https://stackoverflow.com/questions/342969/how-do-i-get-bash-completion-to-work-with-aliases

Basically we just add the following line to git.completion.sh: __git_complete gco _git_checkout

I wanted to make a merge request but thought to make an issue first to check 2 things:

• Is this something you want to have enabled by default?
• are there any more commands where enabling autocomplete on the aliasses would help?