doc/examples/{de,en}code_audio: fix includes

Consistent with other examples.

doc/examples/decode_audio.c

@@ -31,9 +31,9 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "libavcodec/avcodec.h"
+#include <libavcodec/avcodec.h>
 
-#include "libavutil/frame.h"
+#include <libavutil/frame.h>
 
 #define AUDIO_INBUF_SIZE 20480
 #define AUDIO_REFILL_THRESH 4096

doc/examples/encode_audio.c

@@ -31,12 +31,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "libavcodec/avcodec.h"
+#include <libavcodec/avcodec.h>
 
-#include "libavutil/channel_layout.h"
-#include "libavutil/common.h"
-#include "libavutil/frame.h"
-#include "libavutil/samplefmt.h"
+#include <libavutil/channel_layout.h>
+#include <libavutil/common.h>
+#include <libavutil/frame.h>
+#include <libavutil/samplefmt.h>
 
 /* check that a given sample format is supported by the encoder */
 static int check_sample_fmt(const AVCodec *codec, enum AVSampleFormat sample_fmt)