Fixed class binding quotation mark typo

On line 186 there is a class binding quotation mark typo inside the <a> tag on the router configuration example that leads to an error when used. Simply changed
:class="{'active-link': isActive, 'active-link-exact": isExactActive}
to
:class="{'active-link': isActive, 'active-link-exact': isExactActive}"
in the <a> tag.

src/views/menubar/MenubarDoc.vue

@@ -773,4 +773,4 @@ export default {
         }
     }
 }
-</script>
+</script>