help-docs: Add manage a user's stream subscriptions article.

Adds a new help center article focused on managing a single
user's stream subscriptions.

Creates a shared file for instructions to navigate to a user's
full profile via the right sidebar, which is used in three help
center articles.

Fixes #21795.

templates/zerver/help/add-or-remove-users-from-a-stream.md

@@ -62,12 +62,7 @@ This method is useful if you need to remove one user from multiple streams.
 
 {start_tabs}
 
-1. Hover over a user's name in the right sidebar.
-
-1. Click on the ellipsis (<i class="zulip-icon zulip-icon-ellipsis-v-solid"></i>) to
-   the right of their name.
-
-1. Click **View full profile**.
+{!right-sidebar-view-full-profile.md!}
 
 1. Select the **Streams** tab.
 
@@ -77,3 +72,11 @@ This method is useful if you need to remove one user from multiple streams.
 1. Click the **Unsubscribe** button in that row.
 
 {end_tabs}
+
+## Related topics
+
+* [Browse and subscribe to streams](/help/browse-and-subscribe-to-streams)
+* [Unsubscribe from a stream](/help/unsubscribe-from-a-stream)
+* [Manage a user's stream subscriptions](/help/manage-user-stream-subscriptions)
+* [Restrict stream invitation](/help/configure-who-can-invite-to-streams)
+* [Set default streams for new users](/help/set-default-streams-for-new-users)

templates/zerver/help/include/right-sidebar-view-full-profile.md

@@ -0,0 +1,6 @@
+1. Hover over a user's name in the right sidebar.
+
+1. Click on the ellipsis (<i class="zulip-icon zulip-icon-ellipsis-v-solid"></i>)
+   to the right of their name.
+
+1. Click **View full profile**.

templates/zerver/help/include/sidebar_index.md

@@ -157,6 +157,7 @@
 * [Restrict visibility of email addresses](/help/restrict-visibility-of-email-addresses)
 * [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)
 * [Restrict name and email changes](/help/restrict-name-and-email-changes)
 * [Restrict profile picture changes](/help/restrict-profile-picture-changes)
 * [Restrict permissions of new members](/help/restrict-permissions-of-new-members)

templates/zerver/help/manage-user-stream-subscriptions.md

@@ -0,0 +1,64 @@
+# Manage a user's stream subscriptions
+
+## View a user's stream subscriptions
+
+!!! warn ""
+
+      Note that the list of a user's **Subscribed streams** will be limited to
+      streams for which [you can see all subscribers](/help/stream-permissions).
+
+{start_tabs}
+
+{!right-sidebar-view-full-profile.md!}
+
+1. Select the **Streams** tab.
+
+{end_tabs}
+
+## Subscribe a user to a stream
+
+Organization administrators can configure which
+[roles](/help/roles-and-permissions) have access to [subscribe
+other users to a stream][configure-invites].
+
+{start_tabs}
+
+{relative|stream|all}
+
+1. Select a stream.
+
+{!select-stream-view-subscribers.md!}
+
+1. Under **Add subscribers**, enter the user's name or email address.
+
+1. Click **Add**.
+
+{end_tabs}
+
+## Unsubscribe a user from stream(s)
+
+{!admin-only.md!}
+
+Anyone can always [unsubscribe themselves from a
+stream](/help/unsubscribe-from-a-stream).
+
+{start_tabs}
+
+{!right-sidebar-view-full-profile.md!}
+
+1. Select the **Streams** tab.
+
+1. Under **Subscribed streams**, find the stream you would like
+   to remove the user from.
+
+1. Click the **Unsubscribe** button in that row.
+
+{end_tabs}
+
+## Related topics
+
+* [Stream permissions](/help/stream-permissions)
+* [Roles and permissions](/help/roles-and-permissions)
+* [Add or remove users from a stream](/help/add-or-remove-users-from-a-stream)
+
+[configure-invites]: /help/configure-who-can-invite-to-streams

templates/zerver/help/view-someones-profile.md

@@ -24,12 +24,7 @@ streams for which [you can see all subscribers](/help/stream-permissions).
 
 {start_tabs}
 
-1. Hover over a user's name in the right sidebar.
-
-1. Click on the ellipsis (<i class="zulip-icon zulip-icon-ellipsis-v-solid"></i>) to
-   the right of their name.
-
-1. Click **View full profile**.
+{!right-sidebar-view-full-profile.md!}
 
 {end_tabs}