Suggestion: better error message when an ambiguous checkout is executed

[Mahmoud Al-Qudsi <mqudsi@neosmart.net>]

Hello,

The default git behavior when attempting to `git checkout xxx` for
some value of "xxx" that cannot be resolved to a single, unique
file/path/branch/tag/commit/etc is to display the following:

> error: pathspec 'xxx' did not match any file(s) known to git

Unfortunately, this is (IMHO) at best misleading when the actual case
is that "git could not unambiguously resolve pathspec xxx"

Can the case where xxx _was_ resolved but to more than one value be
improved in both utility and comprehensibility by providing an error
message that

1) indicates that xxx was a valid pathspec, but not a unique one
2) provides a list of unique pathspecs that xxx matched against

e.g. in the case where xxx is the name of a branch on both origin1 and
origin2, it would be ideal if git could instead report

> error: pathspec 'xxx' could not be uniquely resolved
> xxx can refer to one of the following:
> * branch origin1/xxx
> * branch origin2/xxx

or, less ideally but much simpler, only the first line of that message?

Thank you,

Mahmoud Al-Qudsi
NeoSmart Technologies