Merge pull request #12164 from nextcloud/backport/12163/stable30

[stable30] chore: Remove unused subsections and add note about CSS variables section

developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_30.rst

@@ -31,6 +31,9 @@ Capabilities
 Front-end changes
 -----------------
 
+The overall design was changed to be less round and more compact,
+as a part of this some CSS variables were added and other deprecated with Nextcloud 30, see :ref:`cssvars`.
+
 Clickable area
 ^^^^^^^^^^^^^^
 The size of the CSS variable ``--clickable-area`` variable has shrunk from ``44px`` to ``34px``.
@@ -100,19 +103,6 @@ When using Webpack:
     + import { getCSPNonce } from '@nextcloud/auth'
     + __webpack_nonce__ = getCSPNonce()
 
-
-Added APIs
-^^^^^^^^^^
-
-Changed APIs
-^^^^^^^^^^^^
-
-Removed APIs
-^^^^^^^^^^^^
-
-Removed globals
-^^^^^^^^^^^^^^^
-
 Deprecated APIs
 ^^^^^^^^^^^^^^^
 
@@ -293,6 +283,3 @@ Removed APIs
 
 - ``OCP\Util::isValidFileName`` was deprecated in 8.1.0 and is now removed, use either ``OCP\Files\Storage\IStorage::verifyPath`` or the new ``OCP\Files\IFilenameValidator``.
 - ``OCP\Util::getForbiddenFileNameChars`` was removed, use either ``OCP\Files\Storage\IStorage::verifyPath`` or the new ``OCP\Files\IFilenameValidator`` for filename validation.
-
-Removed events
-^^^^^^^^^^^^^^