Update link to the Server forum category (#7309)

Let's Encrypt closed it in favor of the Help category.

https://community.letsencrypt.org/t/closing-the-server-category/93016

CHANGELOG.md

@@ -10,7 +10,9 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 
 ### Changed
 
-*
+* If Certbot fails to rollback your server configuration, the error message
+  links to the Let's Encrypt forum. Change the link to the Help category now
+  that the Server category has been closed.
 
 ### Fixed
 

certbot/client.py

@@ -624,7 +624,7 @@ class Client(object):
             reporter.add_message(
                 "An error occurred and we failed to restore your config and "
                 "restart your server. Please post to "
-                "https://community.letsencrypt.org/c/server-config "
+                "https://community.letsencrypt.org/c/help "
                 "with details about your configuration and this error you received.",
                 reporter.HIGH_PRIORITY)
             raise