media: doc: properly format ToC headings

"class:: toc-title" was a workaround for older Sphinx versions that are
no longer supported.

The canonical way to add a heading to the ToC is to use :caption:.
Do that.

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231027081830.195056-10-vegard.nossum@oracle.com

Documentation/userspace-api/media/cec/cec-api.rst

@@ -10,13 +10,8 @@ Part V - Consumer Electronics Control API
 This part describes the CEC: Consumer Electronics Control
 
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+    :caption: Table of Contents
     :maxdepth: 5
     :numbered:
 

Documentation/userspace-api/media/drivers/index.rst

@@ -21,13 +21,8 @@ more details.
 
 For more details see the file COPYING in the source distribution of Linux.
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+	:caption: Table of Contents
 	:maxdepth: 5
 	:numbered:
 

Documentation/userspace-api/media/dvb/dvbapi.rst

@@ -27,13 +27,8 @@ Part II - Digital TV API
 
 **Version 5.10**
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+    :caption: Table of Contents
     :maxdepth: 5
     :numbered:
 

Documentation/userspace-api/media/index.rst

@@ -21,13 +21,8 @@ Documentation/driver-api/media/index.rst
     media devices;
 
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+    :caption: Table of Contents
     :maxdepth: 1
 
     intro

Documentation/userspace-api/media/mediactl/media-controller.rst

@@ -7,13 +7,8 @@
 Part IV - Media Controller API
 ##############################
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+    :caption: Table of Contents
     :maxdepth: 5
     :numbered:
 

Documentation/userspace-api/media/rc/remote_controllers.rst

@@ -7,13 +7,8 @@
 Part III - Remote Controller API
 ################################
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+    :caption: Table of Contents
     :maxdepth: 5
     :numbered:
 

Documentation/userspace-api/media/v4l/v4l2.rst

@@ -11,13 +11,8 @@ This part describes the Video for Linux API version 2 (V4L2 API) specification.
 
 **Revision 4.5**
 
-.. only:: html
-
-   .. class:: toc-title
-
-        Table of Contents
-
 .. toctree::
+    :caption: Table of Contents
     :numbered:
     :maxdepth: 5