graft: correct documentation about options can be reapplied

Now options --user and --date can be reapplied after we hit a conflict.

Differential Revision: https://phab.mercurial-scm.org/D3678

mercurial/commands.py

@@ -2164,7 +2164,7 b' def graft(ui, repo, *revs, **opts):'
     .. note::
 
        The -c/--continue option does not reapply earlier options, except
-       for --force.
+       for --force, --user and --date.
 
     .. container:: verbose