graft: clarify in help that `-r` is not just optional
Positional parameters are also treated as revisions, but the order of revisions
matters and it will often be wrong if the user understands it as `-r` taking
multiple revisions as `-r REV1 REV2`.
(Alternatively, `-r` could be turned into a no-op flag as the documentation
suggests. That would however be less "semantic markup" and I agree with the
implementation in 55e7f352b1d3 but not the documentation.)
https://bz.mercurial-scm.org/619
$ hg init
$ echo a > a
$ hg ci -Ama
adding a
$ echo b > b
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ hg ci -Amb
adding b
$ hg co -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Fast-forward:
$ hg merge b
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -Ammerge
Bogus fast-forward should fail:
$ hg merge b
abort: merging with a working directory ancestor has no effect
[255]
Even with strange revset (issue4465)
$ hg merge ::.
abort: merging with a working directory ancestor has no effect
[255]