user docs: Update collapse-a-message.

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

@@ -1,13 +1,12 @@
 # Collapse a message
 
-Zulip allows you to collapse messages by hiding their contents to reduce message
-clutter.
+Collapse messages that you don't want to see. Zulip sometimes automatically
+partially collapses long messages. This feature is different, and will fully
+remove the message content from view.
 
 {!message-actions-menu.md!}
 
-3. Click on the **Collapse** option from the actions dropdown to collapse a
-message.
+3. Click on **Collapse**.
 
-!!! tip ""
-    To uncollapse a message, click the **[More...]** hyperlink near the
-    bottom of a collapsed message.
+To un-collapse a message, click **[More...]** at the bottom of the collapsed
+message.

templates/zerver/help/moderating-open-organizations.md

@@ -27,6 +27,8 @@ is a big part of making an open community work.
 * [Change users' names](/help/change-a-users-name) (e.g. to "Spammer")
 * [Deactivate bots](/help/deactivate-or-reactivate-a-bot) or
   [delete custom emoji](/help/add-custom-emoji#delete-a-custom-emoji).
+* Instruct users to [collapse](/help/collapse-a-message) messages that they don't
+  want to see.
 
 ## In the works