debugdiscovery: fix a typo in the help

Differential Revision: https://phab.mercurial-scm.org/D12372

mercurial/debugcommands.py

@@ -1020,7 +1020,7 b' def debugdirstateignorepatternshash(ui, '
             b'',
             b'remote-as-revs',
             b"",
-            b'use local as remote, with only these these revisions',
+            b'use local as remote, with only these revisions',
         ),
     ]
     + cmdutil.remoteopts