handbook page update

handbook page : Local SlackSlack Slack is a Collaborative Group Chat Platform https://slack.com/. The WordPress community has its own Slack Channel at https://make.wordpress.org/chat/. Teams

Please. update message
from “Slack for the Korean WordPress Community.”
to “Slack for the Korean WordPress Community. Access using your @chat.wordpress.orgWordPress.org The community site where WordPress code is created and shared by the users. This is where you can download the source code for WordPress core, plugins and themes as well as the central location for community conversations and organization. https://wordpress.org/ e-mail address.”