cmdutil: return underscore-separate name from check_at_most_one_arg()...
cmdutil: return underscore-separate name from check_at_most_one_arg()
As noticed by Yuya, when I changed the function (during review) to
work with underscore-separated names as input, I forgot to make sure
the returned name was also underscore-separated. We don't have any
cases where it matters yet, but it should still clearly be fixed.
Instead of converting the hyphen-separated value we already have in
`previous`, I'm changing it so we convert to the underscore-separated
values to be hyphen-separated only when we need to display them. This
will also help a coming change where we allow the inputs to native
strings instead only bytes.
Differential Revision:
https://phab.mercurial-scm.org/D7698
