help center: Document viewing @-mentions.

Adds "View your mentions" page to document how to access @-mentions
and the @ indicator for unread @-mentions on desktop/web and mobile.

Fixes #23422.

Co-authored-by: Alya Abbott <alya@zulip.com>

templates/zerver/help/include/sidebar_index.md

@@ -81,6 +81,7 @@
 * [Marking messages as read](/help/marking-messages-as-read)
 * [Marking messages as unread](/help/marking-messages-as-unread)
 * [Emoji reactions](/help/emoji-reactions)
+* [View your mentions](/help/view-your-mentions)
 * [Star a message](/help/star-a-message)
 * [View and browse images](/help/view-and-browse-images)
 * [View messages sent by a user](/help/view-messages-sent-by-a-user)

templates/zerver/help/mention-a-user-or-group.md

@@ -72,3 +72,4 @@ streams](/help/stream-notifications).
 
 * [Restrict wildcard mentions](/help/restrict-wildcard-mentions)
 * [Quote and reply](/help/quote-and-reply)
+* [View your mentions](/help/view-your-mentions)

templates/zerver/help/pm-mention-alert-notifications.md

@@ -71,3 +71,4 @@ the alert word is included in a message. Alert words are case-insensitive.
 * [Mobile notifications](/help/mobile-notifications)
 * [Restrict wildcard mentions](/help/restrict-wildcard-mentions)
 * [Stream notifications](/help/stream-notifications)
+* [View your mentions](/help/view-your-mentions)

templates/zerver/help/star-a-message.md

@@ -24,9 +24,9 @@ Starred messages have a filled in star (<i class="fa fa-star"></i>) to
 their right.  You can unstar a message using the same instructions
 used to star it.
 
-## Access your starred messages
+## View your starred messages
 
-You can access your starred messages by clicking **Starred messages** in the
+You can view your starred messages by clicking **Starred messages** in the
 left sidebar, or by [searching](/help/search-for-messages) for `is:starred`.
 
 By default, Zulip displays the number of starred messages in the left

templates/zerver/help/view-your-mentions.md

@@ -0,0 +1,45 @@
+# View your mentions
+
+You can [mention a user or a group](/help/mention-a-user-or-group) to call their
+attention to a message. To make such messages easy to find, Zulip lets you view
+the messages where you were mentioned from a dedicated tab.
+
+!!! warn ""
+
+    Because [silent mentions](/help/mention-a-user-or-group#silently-mention-a-user)
+    are designed not to attract attention, they are excluded from the **Mentions** tab.
+
+## View your mentions
+
+{start_tabs}
+
+{tab|desktop-web}
+
+1. Click **Mentions** in the left sidebar.
+
+1. Browse your mentions. You can click on a message recipient bar to go
+   to the conversation where you were mentioned.
+
+!!! tip ""
+    You can also [search your mentions](/help/search-for-messages) using the
+    `is:mentioned` flag.
+
+{tab|mobile}
+
+1. Tap the **Mentions**
+   (<img src="/static/images/help/mobile-at-sign-icon.svg" alt="at-sign" class="mobile-icon"/>)
+   tab at the top of the app.
+
+1. Browse your mentions. You can tap on a message recipient bar to go
+   to the conversation where you were mentioned.
+
+{end_tabs}
+
+Topics with unread @-mentions are marked with an **@** indicator next to the number
+of unread messages.
+
+## Related articles
+
+* [Mention a user or group](/help/mention-a-user-or-group)
+* [PMs, mentions, and alerts](/help/pm-mention-alert-notifications#pms-mentions-and-alerts)
+* [Reading strategies](/help/reading-strategies)