hgweb: fix border-radius for standards-based browsers

While here, remove an old gecko-specific property, as gecko has
supported the unprefixed version for many years.

mercurial/templates/static/style-paper.css

@@ -88,8 +88,8 b' form.search div#hint {'
   background: #ffc;
   font-size: 70%;
   border: 1px solid yellow;
-  -moz-border-radius: 5px; /* this works only in camino/firefox */
   -webkit-border-radius: 5px; /* this is just for Safari */
+  border-radius: 5px;
 }
 
 form.search:hover div#hint { display: block; }