minor mistake in doc

src/sage/graphs/digraph_generators.py

@@ -771,7 +771,7 @@ def nauty_posetg(self, options='', debug=False):
         - ``options`` -- string (default: ``""``); a string passed to
           ``genposetg`` as if it was run at a system command line.
           At a minimum, you *must* pass the number of vertices you desire
-          and a choice between ``o`` and ``t``` for the output order.
+          and a choice between ``o`` and ``t`` for the output order.
 
         - ``debug`` -- boolean (default: ``False``); if ``True`` the first line
           of ``genposetg``'s output to standard error is captured and the first