docs: Fix a couple of warnings from the docs build.

docs/libs/gst-plugins-base-libs-sections.txt

@@ -454,7 +454,6 @@ gst_mixer_message_parse_volume_changed
 gst_mixer_message_parse_options_list_changed
 
 <SUBSECTION Standard>
-GstMixer
 GstMixerClass
 GST_TYPE_MIXER
 GST_TYPE_MIXER_TYPE

gst-libs/gst/interfaces/mixer.h

@@ -85,17 +85,17 @@ typedef enum
 /**
  * GstMixerFlags:
  * @GST_MIXER_FLAG_NONE: No flags
- * @GST_MIXER_FLAG_AUTO_NOTIFICATIONS: The mixer implementation automatically sends
- *    notification messages.
- * @GST_MIXER_FLAG_HAS_WHITELIST: The mixer implementation flags tracks that should
- *    be displayed by default (whitelisted). Since: 0.10.23
- *
+ * @GST_MIXER_FLAG_AUTO_NOTIFICATIONS: The mixer implementation automatically
+ *    sends notification messages.
+ * @GST_MIXER_FLAG_HAS_WHITELIST: The mixer implementation flags tracks that
+ *    should be displayed by default (whitelisted). Since: 0.10.23
  * @GST_MIXER_FLAG_GROUPING: The mixer implementation will leave some controls
  *    marked without either input or output.  Controls marked as input or
  *    output should be grouped with input & output sliders, even if they
  *    are options or bare switches. Since: 0.10.23
  * 
- * Flags for supported features.
+ * Flags indicating which optional features are supported by a mixer
+ * implementation.
  *
  * Since: 0.10.14
  */

gst-libs/gst/video/gstbasevideodecoder.h

@@ -51,9 +51,10 @@ G_BEGIN_DECLS
 #define GST_BASE_VIDEO_DECODER_SRC_NAME     "src"
 
 /**
- *  * GST_BASE_VIDEO_DECODER_FLOW_NEED_DATA:
- *   *
- *    */
+ * GST_BASE_VIDEO_DECODER_FLOW_NEED_DATA:
+ *
+ * Custom GstFlowReturn value indicating that more data is needed.
+ */
 #define GST_BASE_VIDEO_DECODER_FLOW_NEED_DATA GST_FLOW_CUSTOM_SUCCESS