plugins: Fix codec name on AAC encoders

plugins/coreaudio-encoder/encoder.cpp

@@ -1409,7 +1409,7 @@ bool obs_module_load(void)
 	};
 	aac_info.id = "CoreAudio_AAC";
 	aac_info.type = OBS_ENCODER_AUDIO;
-	aac_info.codec = "AAC";
+	aac_info.codec = "aac";
 	aac_info.get_name = aac_get_name;
 	aac_info.destroy = aac_destroy;
 	aac_info.create = aac_create;

plugins/obs-ffmpeg/obs-ffmpeg-audio-encoders.c

@@ -427,7 +427,7 @@ static size_t enc_frame_size(void *data)
 struct obs_encoder_info aac_encoder_info = {
 	.id = "ffmpeg_aac",
 	.type = OBS_ENCODER_AUDIO,
-	.codec = "AAC",
+	.codec = "aac",
 	.get_name = aac_getname,
 	.create = aac_create,
 	.destroy = enc_destroy,

plugins/obs-libfdk/obs-libfdk.c

@@ -305,7 +305,7 @@ static size_t libfdk_frame_size(void *data)
 struct obs_encoder_info obs_libfdk_encoder = {
 	.id = "libfdk_aac",
 	.type = OBS_ENCODER_AUDIO,
-	.codec = "AAC",
+	.codec = "aac",
 	.get_name = libfdk_getname,
 	.create = libfdk_create,
 	.destroy = libfdk_destroy,