Should fix auto-generated follow-up sections like "Hierarchy" or
"Factory details" to be listed under the element name in the
table-of-contents of the document, instead of a stand-alone
"Duplex-Mode" section.
Also cleanup some spurious colon suffix after section names.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5625>
The order of the devices iterator from the SDK is undefined and can
randomly change.
Keep the device-number property for backwards compatibility and
simplicity but prefer the persistent-id property and also use it for the
device provider implementation.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3078>
