dirstate: add a comment about the semantic of `dirstate.clear`
This method is weird, lets flag it as such.
--- a/mercurial/dirstate.py Mon Feb 20 14:05:19 2023 +0100
+++ b/mercurial/dirstate.py Mon Feb 20 11:37:02 2023 +0100
@@ -858,6 +858,9 @@
# XXX since this make the dirstate dirty, we should enforce that it is done
# withing an appropriate change-context that scope the change and ensure it
# eventually get written on disk (or rolled back)
+ # XXX this method is barely used, as a result:
+ # - its semantic is unclear
+ # - do we really needs it ?
def clear(self):
self._map.clear()
self._dirty = True