Merge pull request #3901 from tgxworld/focus_editor_after_inserting_text

UX: Focus composer input after adding text.

app/assets/javascripts/discourse/components/d-editor.js.es6

@@ -380,6 +380,7 @@ export default Ember.Component.extend({
     const insert = `${sel.pre}${text}`;
     this.set('value', `${insert}${sel.post}`);
     this._selectText(insert.length, 0);
+    Ember.run.once("afterRender", () => { $("textarea.d-editor-input").focus(); } );
   },
 
   actions: {