path: remove outdated documentation point from `get_unique_push_path`

This is no longer true.

mercurial/utils/urlutil.py

@@ -522,8 +522,6 b' def get_unique_push_path(action, repo, u'
     This is useful for command and action that does not support multiple
     destination (yet).
 
-    Note that for now, we cannot get multiple destination so this function is "trivial".
-
     The `action` parameter will be used for the error message.
     """
     if dest is None: