Update yields.js (#490)

Author: EirikBirkeland

lib/tags/yields.js

@@ -88,7 +88,7 @@ module.exports = function yields (hexo, args) {
   const nullAlias = () => {
     return `<ul>
       <li><p>${cmd} yields <code>null</code>.</p></li>
-      <li><p>${cmd} can but aliased but otherwise cannot be chained further.</p></li>
+      <li><p>${cmd} can be aliased, but otherwise cannot be chained further.</p></li>
     </ul>`
   }