Markup fix.

Doc/lib/libasyncore.tex

@@ -46,7 +46,7 @@ service) is closed.
 \begin{funcdesc}{loop}{\optional{timeout\optional{, use_poll\optional{,
                        map\optional{,count}}}}}
   Enter a polling loop that terminates after count passes or all open
-  channels have been closed.  All arguments are optional.  The \var(count)
+  channels have been closed.  All arguments are optional.  The \var{count}
   parameter defaults to None, resulting in the loop terminating only
   when all channels have been closed.  The \var{timeout} argument sets the
   timeout parameter for the appropriate \function{select()} or