help: Document how archived channels work now.

Initial bullets closely match in-app confirmation modal.

help/archive-a-channel.md

@@ -2,19 +2,29 @@
 
 {!admin-only.md!}
 
-Archiving a channel will hide the channel from most views in the UI.
-Archiving a channel does not delete a channel's messages, and its
-messages will remain accessible via search and the like, unless you
-first change the channel's access permissions.
+You can archive channels you no longer plan to use. Archiving a channel:
 
-Archiving a channel does not remove subscribers or change its access
-permissions.
+- Removes it from the left sidebar for all users.
+- Prevents new messages from being sent to the channel.
+- Prevents messages in the channel from being edited, deleted, or moved.
 
-Consider [renaming channels](/help/rename-a-channel) rather than
-archiving them where appropriate.
+Archiving a channel does not remove subscribers, or change who can access it.
+Messages in archived channels still appear in [search
+results](/help/search-for-messages), the [combined feed](/help/combined-feed),
+and [recent conversations](/help/recent-conversations).
+
+To hide the content in a channel, you can make it
+[private](/help/change-the-privacy-of-a-channel) and [unsubscribe
+users](/help/manage-user-channel-subscriptions) from it prior to archiving.
 
 ## Archive a channel
 
+!!! warn ""
+
+    Channels can be [unarchived](#unarchiving-archived-channels) only by
+    [contacting support](/help/contact-support) for organizations hosted
+    on Zulip Cloud, or by your self-hosted server's administrator.
+
 {start_tabs}
 
 {tab|desktop-web}
@@ -23,8 +33,8 @@ archiving them where appropriate.
 
 1. Select a channel.
 
-1. Click the **archive** <i class="zulip-icon zulip-icon-archive"></i> icon near the top right
-   corner of the channel settings panel.
+1. Click the **archive** (<i class="zulip-icon zulip-icon-archive"></i>) icon
+   in the upper right corner of the channel settings panel.
 
 1. Approve by clicking **Confirm**.
 
@@ -32,22 +42,19 @@ archiving them where appropriate.
 
     You can also hover over a channel in the left sidebar, click on the
     **ellipsis** (<i class="zulip-icon zulip-icon-more-vertical"></i>), and
-    select **Channel settings** to access the **archive**
-    <i class="zulip-icon zulip-icon-archive"></i> icon.
+    select **Channel settings** to access settings for the channel.
 
 {end_tabs}
 
-!!! warn ""
-
-    Archiving a channel is currently irreversible via the UI.
-
 ## Unarchiving archived channels
 
+Zulip Cloud organizations that need to unarchive a channel can [contact Zulip
+support](/help/contact-support).
+
 If you are self-hosting, you can unarchive an archived channel using the
 `unarchive_channel` [management command][management-command]. This will restore
 it as a private channel with shared history, and subscribe all organization
-owners to it. If you are using Zulip Cloud, you can [contact us](/help/contact-support)
-for help.
+owners to it.
 
 [management-command]:
 https://zulip.readthedocs.io/en/latest/production/management-commands.html#other-useful-manage-py-commands
@@ -59,4 +66,3 @@ https://zulip.readthedocs.io/en/latest/production/management-commands.html#other
 * [Delete a topic](/help/delete-a-topic)
 * [Message retention policy](/help/message-retention-policy)
 * [Channel permissions](/help/channel-permissions)
-* [Zulip Cloud or self-hosting?](/help/zulip-cloud-or-self-hosting)