repoview: remove incorrect documentation of the function

In repoview.py, computeunserved() and computemutable() functions had the same
documentation. The documentation of computemutable() is wrong. I was unable to
write documentation for the function but it's better to not having the
documentation than having it wrong.

Differential Revision: https://phab.mercurial-scm.org/D1016

mercurial/repoview.py

@@ -99,9 +99,6 def computeunserved(repo):
         return hiddens
 
 def computemutable(repo):
-    """compute the set of revision that should be filtered when used a server
-
-    Secret and hidden changeset should not pretend to be here."""
     assert not repo.changelog.filteredrevs
     # fast check to avoid revset call on huge repo
     if any(repo._phasecache.phaseroots[1:]):