FR: Add a jj git colocate command

[PhilipMetzger]

Is your feature request related to a problem? Please describe.

We've repeatedly had the request in the Discord for a command which eases the transition from a bare Git backed repo (initialized with jj git init), to a colocated (so moving the .git directory adjacent to .jj) one. This command should be responsible for doing that.

Implementation Steps

Add a new file under named colocate.rs under cli/src/commands/git/ (don't forget to add mod colocate to the mod.rs).
Implement these steps with code: https://martinvonz.github.io/jj/latest/git-compatibility/#converting-a-repo-into-a-co-located-repo

[estk]

@PhilipMetzger how does this differ from jj git init --colocate?

[essiene]

@PhilipMetzger how does this differ from jj git init --colocate?

IIUC, this takes a jj git backed repo presumably created by jj git init and turns it into a colocated repo.

It wasn't very clear from the initial description until I followed the link.

[PhilipMetzger]

@PhilipMetzger how does this differ from jj git init --colocate?

IIUC, this takes a jj git backed repo presumably created by jj git init and turns it into a colocated repo.

This is correct, I'll edit the description.