examples/encoding: rename to decoding_encoding.c as the file is an example for both.

Signed-off-by: NMichael Niedermayer <michaelni@gmx.at>

doc/examples/Makefile

@@ -3,7 +3,7 @@ FFMPEG_LIBS=libavdevice libavformat libavfilter libavcodec libswscale libavutil
 CFLAGS+=$(shell pkg-config  --cflags $(FFMPEG_LIBS))
 LDFLAGS+=$(shell pkg-config --libs $(FFMPEG_LIBS))
 
-EXAMPLES=encoding filtering metadata muxing
+EXAMPLES=decoding_encoding filtering metadata muxing
 
 OBJS=$(addsuffix .o,$(EXAMPLES))