provide completions for git remotes with remote as prefix

Sanity checks

• My issue relates to a specific CLI completion spec (e.g. git checkout is missing options in git completion spec). If your issue is more general, please create your issue here: withfig/fig
• I have searched github.com/withfig/autocomplete/issues and there are no duplicates of my issue
• I would like to work on this.

What CLI tool does this relate to?

git

Which statement makes the most sense?

There is a bug with this completion spec

Issue Details

1. When I type git commit and request completions, I expect to see origin/branch_name for example.
2. This code prevents that from happening: https://github.com/withfig/autocomplete/blob/7828841c763347a32d85ae3c072c64f71649bac2/src/git.ts#L92-L96

These changes allow that to show up in the completions list:

https://github.com/microsoft/vscode/pull/241675/files

I'm wondering if you are open to this contribution.