[calls] media-codecs: Clarify that codec availability should be checked before use

[Evangelos Ribeiro Tzaras <devrtz src gnome org>]

commit 0b8fb4a448fd0249e8a86c92c4b7d77ca9473cf7
Author: Evangelos Ribeiro Tzaras <devrtz fortysixandtwo eu>
Date:   Thu Nov 25 05:34:44 2021 +0100

    media-codecs: Clarify that codec availability should be checked before use

 plugins/sip/gst-rfc3551.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/plugins/sip/gst-rfc3551.c b/plugins/sip/gst-rfc3551.c
index cd022b47..9693557b 100644
--- a/plugins/sip/gst-rfc3551.c
+++ b/plugins/sip/gst-rfc3551.c
@@ -66,7 +66,9 @@ media_codec_available_in_gst (MediaCodecInfo *codec) {
  *
  * @name: The name of the codec
  *
- * Returns: (transfer none): A #MediaCodecInfo, if found
+ * Returns: (transfer none): A #MediaCodecInfo, if found.
+ * You should check if the codec is available on your system before
+ * trying to use it with media_codec_available_in_gst()
  */
 MediaCodecInfo *
 media_codec_by_name (const char *name)
@@ -85,7 +87,9 @@ media_codec_by_name (const char *name)
  *
  * @payload_id: The payload id (see RFC 3551, 3555, 4733, 4855)
  *
- * Returns: (transfer none): A #MediaCodecInfo, if found
+ * Returns: (transfer none): A #MediaCodecInfo, if found.
+ * You should check if the codec is available on your system before
+ * trying to use it with media_codec_available_in_gst()
  */
 MediaCodecInfo *
 media_codec_by_payload_id (guint payload_id)