Apply the git precendence rules to the given shorthand to determine
which reference the user is referring to.
@param out_ pointer in which to store the reference
@param repo the repository in which to look
@param shorthand the short name for the reference
@return 0 or an error code
Lookup a reference by DWIMing its short name
Apply the git precendence rules to the given shorthand to determine which reference the user is referring to.
@param out_ pointer in which to store the reference @param repo the repository in which to look @param shorthand the short name for the reference @return 0 or an error code