[PATCH proxmox-backup 2/3] docs: mention still missing field in the configuration subtree

[Christian Ebner <c.ebner@proxmox.com>]

There are several new menu entries, which still are not listed in
the documentation. Add them including a concise description of the
functionality they refer to.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
 docs/gui.rst | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/docs/gui.rst b/docs/gui.rst
index 7e59ac102..d71f774a3 100644
--- a/docs/gui.rst
+++ b/docs/gui.rst
@@ -93,9 +93,15 @@ WebAuthn, and HTTP proxy configuration. It also contains the following
 subsections:
 
 * **Access Control**: Add and manage users, API tokens, and the permissions
-  associated with these items
-* **Remotes**: Add, edit and remove remotes (see :term:`Remote`)
+  associated with these items.
+* **Remotes**: Add, edit and remove remotes (see :term:`Remote`).
+* **S3 Endpoints**: Add, edit and remove S3 endpoints to be used by datastores.
+* **Traffic Control**: Manage rules for traffic limits on users, networks and
+  timeframes.
 * **Certificates**: Manage ACME accounts and create SSL certificates.
+* **Encryptioin Keys**: Manage encryption keys for tape backups and sync jobs.
+* **Notifications**: Configure notification targets and control when
+  notifications should be send by defining match rules.
 * **Subscription**: Upload a subscription key, view subscription status and
   access a text-based system report.
 
-- 
2.47.3