histedit: make histedit's commands accept revsets (
issue5746)
Earlier the code was only looking for rulehashes and neglecting
all other revision identifiers, this code intercepts the fromrule function
and calls scmutil.revsingle() on anything that is not a rulehash and then
obtains the rulehash from the changectx object returned, rest of the pipeline
follows as it was
Differential Revision: https://phab.mercurial-scm.org/D2394