Fix typo

lib/views/admin/notification.html

@@ -158,7 +158,7 @@
       </p>
 
       <h4>2. Get <code>clientId</code> and <code>clientSecret</code></h4>
-      <h4>3. After clientId nad clientSecret set, click "Connect to Slack" button to start OAuth process.</h4>
+      <h4>3. After clientId and clientSecret set, click "Connect to Slack" button to start OAuth process.</h4>
       <h4>4. Configure Slack on this notification setting screen</h4>
       {% endif %}