Update number-game-errors.html (#845)

Author: yousukka

javascript/introduction-to-js-1/troubleshooting/number-game-errors.html

@@ -84,7 +84,7 @@ <h1>Number guessing game</h1>
         guessField.value = "";
         guessField.focus();
       }
-      guessSubmit.addeventListener("click", checkGuess);
+      guessSubmit.addEventListener("click", checkGuess);
 
       function setGameOver() {
         guessField.disabled = true;