fix regression from id revert on e3e37620 to scroll on messages

src/store/index.js

@@ -101,7 +101,7 @@ export default new Vuex.Store({
     },
     DISPLAY_MESSAGE(state, comment) {
       state.messages = [{ comment }, ...state.messages];
-      document.getElementById("messages").scrollIntoView({ block: "start", inline: "nearest" });
+      if (document.getElementById("content")) document.getElementById("content").scrollIntoView({ block: "start", inline: "nearest" });
       setTimeout(() => {
         state.messages = [];
       }, 3000);