help: Update "User groups".

- Documents user groups new UI.
- Splits documentation into "User groups" and "Manage User groups".

Fixes #18583.

help/include/create-a-stream-instructions.md

@@ -2,7 +2,7 @@
 
 {tab|desktop-web}
 
-{relative|stream|all}
+{relative|gear|stream-settings}
 
 1. Click **Create stream** on the right, or click the **plus**
    (<i class="fa fa-plus"></i>) icon in the upper right.

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

@@ -1,16 +1,18 @@
 {start_tabs}
 
+{tab|desktop-web}
+
 {relative|gear|group-settings}
 
 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 **Create** in the bottom right corner
+1. Fill out the requested info, and 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.
+!!! warn ""
+
+    **Note**: You will only see the **Create user group** button if you have
+    permission to create user groups.
 
 {end_tabs}

help/include/sidebar_index.md

@@ -120,6 +120,7 @@
 * [User cards](/help/user-cards)
 * [View someone's profile](/help/view-someones-profile)
 * [Direct messages](/help/direct-messages)
+* [User groups](/help/user-groups)
 
 ## Streams & topics
 * [Streams and topics](/help/streams-and-topics)
@@ -188,7 +189,7 @@
 * [Custom profile fields](/help/custom-profile-fields)
 * [Configure default new user settings](/help/configure-default-new-user-settings)
 * [Configure organization language](/help/configure-organization-language)
-* [User groups](/help/user-groups)
+* [Manage user groups](/help/manage-user-groups)
 * [Change a user's role](/help/change-a-users-role)
 * [Change a user's name](/help/change-a-users-name)
 * [Manage a user's stream subscriptions](/help/manage-user-stream-subscriptions)