decklink: Increase section level of video sink/source element documentation

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>

subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosink.cpp

@@ -32,7 +32,7 @@
  * Playout a 1080p25 test-video to the SDI-Out of Card 0. Devices are numbered
  * starting with 0.
  *
- * # Duplex-Mode:
+ * ## Duplex-Mode
  * Certain DechLink Cards like the Duo2 or the Quad2 contain two or four
  * independent SDI units with two connectors each. These units can operate either
  * in half- or in full-duplex mode.
@@ -40,7 +40,7 @@
  * The Duplex-Mode of a Card can be configured using the `duplex-mode`-Property.
  * Cards that to not support Duplex-Modes are not influenced by the property.
  *
- * ## Half-Duplex-Mode (default):
+ * ### Half-Duplex-Mode (default)
  * By default decklinkvideosink will configure them into half-duplex mode, so that
  * each connector acts as if it were an independent DeckLink Card which can either
  * be used as an Input or as an Output. In this mode the Duo2 can be used as as 4 SDI
@@ -67,7 +67,7 @@
  * Playout a Test-Screen with colored Snow on the first and fourth unit
  * (ie. the Connectors 1-4 of a Duo2 unit).
  *
- * ## Device-Number-Mapping in Half-Duplex-Mode
+ * ### Device-Number-Mapping in Half-Duplex-Mode
  * The device-number to connector-mapping is as follows for the Duo2
  * - `device-number=0` SDI1
  * - `device-number=1` SDI3
@@ -84,11 +84,11 @@
  * - `device-number=6` SDI6
  * - `device-number=7` SDI8
  *
- * ## Full-Duplex-Mode:
+ * ### Full-Duplex-Mode
  * When operating in full-duplex mode, two connectors of a unit are combined to
  * a single device, performing keying with the second connection.
  *
- * ## Device-Number-Mapping in Full-Duplex-Mode
+ * ### Device-Number-Mapping in Full-Duplex-Mode
  * The device-number to connector-mapping in full-duplex-mode is as follows for the Duo2
  * - `device-number=0` SDI1 primary, SDI2 secondary
  * - `device-number=1` SDI3 primaty, SDI4 secondary
@@ -99,13 +99,13 @@
  * - `device-number=2` SDI5 primary, SDI6 secondary
  * - `device-number=3` SDI7 primary, SDI8 secondary
  *
- * # Keying
+ * ## Keying
  * Keying is the process of overlaing Video with an Alpha-Channel on top of an
  * existing Video-Stream. The Duo2 and Quad2-Cards can perform two different
  * Keying-Modes when operated in full-duplex mode. Both modes expect Video with
  * an Alpha-Channel.
  *
- * ## Internal Keyer:
+ * ### Internal Keyer
  * In internal Keying-Mode the primary port becomes an Input and the secondary port
  * an Output. The unit overlays Video played back from the Computer onto the Input
  * and outputs the combined Video-Stream to the Output.
@@ -117,7 +117,7 @@
  *  decklinkvideosink device-number=0 duplex-mode=full keyer-mode=internal video-format=8bit-bgra mode=1080p25
  * ]|
  *
- * ## External Keyer:
+ * ### External Keyer
  * In external Keying-Mode the primary port outputs the alpha-chanel as the
  * luma-value (key-channel). Transparent pixels are black, opaque pixels are white.
  * The RGB-Component of the Video are output on the secondary channel.

subprojects/gst-plugins-bad/sys/decklink/gstdecklinkvideosrc.cpp

@@ -33,7 +33,7 @@
  * Capturing 1080p25 video from the SDI-In of Card 0. Devices are numbered
  * starting with 0.
  *
- * # Duplex-Mode:
+ * ## Duplex-Mode
  * Certain DechLink Cards like the Duo2 or the Quad2 contain two or four
  * independent SDI units with two connectors each. These units can operate either
  * in half- or in full-duplex mode.
@@ -41,7 +41,7 @@
  * The Duplex-Mode of a Card can be configured using the `duplex-mode`-Property.
  * Cards that to not support Duplex-Modes are not influenced by the property.
  *
- * ## Half-Duplex-Mode (default):
+ * ### Half-Duplex-Mode (default)
  * By default decklinkvideosrc will configure them into half-duplex mode, so that
  * each connector acts as if it were an independent DeckLink Card which can either
  * be used as an Input or as an Output. In this mode the Duo2 can be used as as 4 SDI
@@ -75,7 +75,7 @@
  * Playout a Test-Screen with colored Snow on the first and fourth unit
  * (ie. the Connectors 1-4 of a Duo2 unit).
  *
- * ## Device-Number-Mapping in Half-Duplex-Mode
+ * ### Device-Number-Mapping in Half-Duplex-Mode
  * The device-number to connector-mapping in half-duplex-mode is as follows for the Duo2
  * - `device-number=0` SDI1
  * - `device-number=1` SDI3
@@ -92,7 +92,7 @@
  * - `device-number=6` SDI6
  * - `device-number=7` SDI8
  *
- * ## Full-Duplex-Mode:
+ * ### Full-Duplex-Mode
  * When operating in full-duplex mode, two connectors of a unit are combined to
  * a single device, performing extra processing with the second connection.
  *
@@ -119,7 +119,7 @@
  * Capturing Video on the primary port of device 0, output flipped version of the
  * video on secondary port of the same device.
  *
- * ## Device-Number-Mapping in Full-Duplex-Mode
+ * ### Device-Number-Mapping in Full-Duplex-Mode
  * The device-number to connector-mapping in full-duplex-mode is as follows for the Duo2
  * - `device-number=0` SDI1 primary, SDI2 secondary
  * - `device-number=1` SDI3 primaty, SDI4 secondary
@@ -1766,4 +1766,4 @@ gst_decklink_video_src_change_state (GstElement * element,
 out:
 
   return ret;
-}
+}