add space on end to more feedback

public/main/js/app.js

@@ -303,6 +303,7 @@ function initializeChat() {
                             chatInputElement.value = inputValue.slice(0, lastWordIndex) + `@${user}` + inputValue.slice(lastWordIndex + lastWord.length);
                         }
                         userList.classList.add("hidden");
+                        chatInputElement.value += " ";
                         chatInputElement.focus();
                     };
                     const color = getUserColor(user);