rst2man: avoid italic for references

The links to other manpages used both italic and bold text nested
within each other. The \fP (select previous font) macro was used
incorrectly to "reset" the nested fonts resulting in:

  <roman> text <italic> <bold> hg <italic> (1) <bold> more text

with no switch back to roman. This stops the bleeding and removes the
ugly italic (underline) from the manpage links.

doc/rst2man.py

@@ -217,7 +217,7 b' class Translator(nodes.NodeVisitor):'
 
                 'option_list_item' : ('.TP\n', ''),
                 
-                'reference' : (r'\fI\%', r'\fP'),
+                'reference' : (r'\%', r'\:'),
                 'emphasis': ('\\fI', '\\fP'),
                 'strong' : ('\\fB', '\\fP'),
                 'term' : ('\n.B ', '\n'),