fix double quote linting error

Author: natboehm

app/controllers/keyword/index.js

@@ -13,13 +13,13 @@ export default Controller.extend(PaginationMixin, {
 
     currentSortBy: computed('sort', function() {
         if (this.get('sort') === 'downloads') {
-            return "All Time Downloads";
+            return 'All Time Downloads';
         } else if (this.get('sort') === 'recent-downloads') {
-            return "Recent Downloads";
+            return 'Recent Downloads';
         } else if (this.get('sort') === 'alpha') {
-            return "Alphabetical";
+            return 'Alphabetical';
         } else {
-            return "Recent Downloads";
+            return 'Recent Downloads';
         }
     }),
 });