simplify example

I've seen user(http://*) confuse someone who didn't know pagespecs to think
that just http://* would moderate all comments to every page, or something
like that.

IkiWiki/Plugin/moderatedcomments.pm

@@ -19,7 +19,7 @@ sub getsetup () {
 		},
 		moderate_pagespec => {
 			type => 'pagespec',
-			example => 'user(http://*)',
+			example => '*',
 			description => 'PageSpec matching users or comment locations to moderate',
 			link => 'ikiwiki/PageSpec',
 			safe => 1,