Instead of `.js.handlebars` use `.hbs` for handlebars templates

app/assets/javascripts/discourse/helpers/plugin-outlet.js.es6

@@ -13,7 +13,7 @@
    Then any handlebars files you create in the `connectors/evil-trout` directory
    will automatically be appended. For example:
 
-   plugins/hello/assets/javascripts/discourse/templates/connectors/evil-trout/hello.handlebars
+   plugins/hello/assets/javascripts/discourse/templates/connectors/evil-trout/hello.hbs
 
    With the contents:
 

app/assets/javascripts/discourse/initializers/live-development.js.es6

@@ -38,10 +38,10 @@ export default {
         if (me === "refresh") {
           // Refresh if necessary
           document.location.reload(true);
-        } else if (me.name.substr(-10) === "handlebars") {
+        } else if (me.name.substr(-10) === "hbs") {
 
           // Reload handlebars
-          var js = me.name.replace(".handlebars", "").replace("app/assets/javascripts", "/assets");
+          var js = me.name.replace(".hbs", "").replace("app/assets/javascripts", "/assets");
           $LAB.script(js + "?hash=" + me.hash).wait(function() {
             var templateName;
             templateName = js.replace(".js", "").replace("/assets/", "");

app/assets/javascripts/discourse/templates/composer.hbs

@@ -70,7 +70,7 @@
             {{composer-text-area tabindex="4" value=model.reply}}
             {{popupInputTip validation=view.replyValidation shownAt=view.showReplyTip}}
           </div>
-          <!-- keep the classes here in sync with post.js.handlebars -->
+          <!-- keep the classes here in sync with post.hbs -->
           <div class='preview-wrapper regular'>
             <div id='wmd-preview' {{bind-attr class="hidePreview:hidden :cooked"}}></div>
           </div>