fix(docs): update path to edit a file

docs/index.html

@@ -123,7 +123,7 @@
             if (vm.route.path.search('i18n') === -1) {
               var dynamicText =
                 '[<i class="far fa-edit"></i> Edit this guide on GitHub](' +
-                'https://github.com/freeCodeCamp/freeCodeCamp/blob/master/docs/' +
+                'https://github.com/freeCodeCamp/freeCodeCamp/blob/main/docs/' +
                 vm.route.file +
                 ')';
             }