help: Update documentation to use new "#groups" UI.

help/include/how-to-create-a-user-group.md

@@ -1,12 +1,14 @@
 {start_tabs}
 
-{settings_tab|user-groups-admin}
+{relative|group|all}
 
-1. Click the **Add a new user group** button.
+1. Click **Create user group** on the right, or click the **plus**
+   (<i class="fa fa-plus"></i>) icon in the upper right.
 
 1. Enter a **Name** and **Description**.
 
-1. Click **Save**.
+1. Click **Create** in the bottom right corner
+   of the create user group panel.
 
 1. Find the group in the list below, and add members. Zulip will notify
    everyone who is added.