rust: use 'impl Trait' in method argument of AncestorsIterator
I just didn't know it's stabilized. Let's switch to new convenient syntax.
Differential Revision: https://phab.mercurial-scm.org/D5451
rust: use .rev() for reverse range
Differential Revision: https://phab.mercurial-scm.org/D5450
histedit: add warning message on editing tagged commits (
issue4017)
Differential Revision: https://phab.mercurial-scm.org/D5489