Clarify adding SSH Git dependencies (#13534)
The current instructions say
> prefix a Git-compatible URL (i.e., that you would use with git clone)
with git+.
But this does not work with the URL that Github gives you when you
choose Clone -> SSH via the UI, which is of the form
`git@github.com:astral-sh/uv.git`. If you prefix this with `git+`, i.e.
`git+git@github.com:astral-sh/uv.git`
it does not work.
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Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>