chistedit: change in-progress message

Saying "running histedit" is an artifact of when chistedit was a
separate thing from histedit. I found the message a bit confusing,
since wasn't I running histedit from the beginning, just from the
curses interface?

The whole thing is now histedit, both the curses interface and the
underlying procedure to apply a plan, so let's use a message that
doesn't make a distinction.

hgext/histedit.py

@@ -1497,7 +1497,7 b' def _chistedit(ui, repo, *freeargs, **op'
             ui.write(_("histedit aborted\n"))
             return 0
         if type(rc) is list:
-            ui.status(_("running histedit\n"))
+            ui.status(_("performing changes\n"))
             rules = makecommands(rc)
             filename = repo.vfs.join('chistedit')
             with open(filename, 'w+') as fp: