help: Document settings to automatically unmute/follow topics.

- Adds a "Topic notifications" page, just under "Stream notifications"
  in the left sidebar, using Markdown include blocks for reusability
  in `follow-a-topic.md` and `mute-a-topic.md`.
- Adds a tip block to clarify that disabling followed topic global
  settings will not stop notifications if you already have stream
  level settings enabled.

Fixes part of #27297.

help/follow-a-topic.md

@@ -18,14 +18,11 @@ In muted streams, topics you follow are automatically treated as
 
 ## Configure notifications for followed topics
 
-{start_tabs}
+{!configure-notifications-for-followed-topics.md!}
 
-{settings_tab|notifications}
+## Automatically follow topics
 
-1. In the **Notification triggers** table,
-   toggle the settings for **Followed topics**.
-
-{end_tabs}
+{!automatically-follow-topics.md!}
 
 ## Manage configured topics
 
@@ -39,6 +36,7 @@ In muted streams, topics you follow are automatically treated as
 
 ## Related articles
 
+* [Topic notifications](/help/topic-notifications)
 * [Stream notifications](/help/stream-notifications)
 * [Mute or unmute a topic](/help/mute-a-topic)
 * [Mute or unmute a stream](/help/mute-a-stream)

help/include/automatically-follow-topics.md

@@ -0,0 +1,10 @@
+{start_tabs}
+
+{tab|desktop-web}
+
+{settings_tab|notifications}
+
+1. Under **Topic notifications**, select the desired option from the
+   **Automatically follow topics** dropdown.
+
+{end_tabs}

help/include/automatically-unmute-topics-in-muted-streams.md

@@ -0,0 +1,10 @@
+{start_tabs}
+
+{tab|desktop-web}
+
+{settings_tab|notifications}
+
+1. Under **Topic notifications**, select the desired option from the
+   **Automatically unmute topics in muted streams** dropdown.
+
+{end_tabs}

help/include/configure-notifications-for-followed-topics.md

@@ -0,0 +1,15 @@
+{start_tabs}
+
+{tab|desktop-web}
+
+{settings_tab|notifications}
+
+1. In the **Notification triggers** table,
+   toggle the settings for **Followed topics**.
+
+{end_tabs}
+
+!!! tip ""
+
+    You will receive both followed topics notifications and
+    [stream notifications](/help/stream-notifications) in topics you follow.

help/include/sidebar_index.md

@@ -137,6 +137,7 @@
 
 ## Notifications
 * [Stream notifications](/help/stream-notifications)
+* [Topic notifications](/help/topic-notifications)
 * [Follow a topic](/help/follow-a-topic)
 * [DMs, mentions, and alerts](/help/dm-mention-alert-notifications)
 * [Mute or unmute a stream](/help/mute-a-stream)

help/mute-a-topic.md

@@ -6,6 +6,10 @@
 
 {!configure-topic-notifications.md!}
 
+## Automatically unmute topics in muted streams
+
+{!automatically-unmute-topics-in-muted-streams.md!}
+
 ## Manage configured topics
 
 {!manage-configured-topics.md!}
@@ -14,4 +18,5 @@
 
 * [Mute or unmute a stream](/help/mute-a-stream)
 * [Follow a topic](/help/follow-a-topic)
+* [Topic notifications](/help/topic-notifications)
 * [Mute a user](/help/mute-a-user)

help/topic-notifications.md

@@ -0,0 +1,27 @@
+# Topic notifications
+
+In Zulip, you can configure how you get notified about new messages for topics
+you follow.
+
+In muted streams, topics you follow are automatically treated as
+[unmuted](/help/mute-a-topic), and you can configure when to automatically
+unmute topics.
+
+## Configure notifications for followed topics
+
+{!configure-notifications-for-followed-topics.md!}
+
+## Automatically follow topics
+
+{!automatically-follow-topics.md!}
+
+## Automatically unmute topics in muted streams
+
+{!automatically-unmute-topics-in-muted-streams.md!}
+
+## Related articles
+
+* [Follow a topic](/help/follow-a-topic)
+* [Stream notifications](/help/stream-notifications)
+* [Mute or unmute a topic](/help/mute-a-topic)
+* [Mute or unmute a stream](/help/mute-a-stream)