updated docs

Signed-off-by: Nwusongqing <wusongqing@huawei.com>

en/application-dev/media/Readme-EN.md

@@ -2,9 +2,9 @@
 
 -   [Audio](audio.md)
     -   [Audio Overview](audio-overview.md)
-    -   [Development Guidelines on Audio Playback](audio-playback.md) 
+    -   [Audio Playback Development](audio-playback.md) 
 
-    -   [Development Guidelines on Audio Management](audio-management.md)  
+    -   [Audio Management Development](audio-management.md)  
 
-    -   [Development Guidelines on Audio Recording](audio-recorder.md) 
+    -   [Audio Recording Development](audio-recorder.md) 
 

en/application-dev/media/audio-management.md

-# Development Guidelines on Audio Management<a name="EN-US_TOPIC_0000001147178551"></a>
+# Audio Management Development<a name="EN-US_TOPIC_0000001147178551"></a>
 
 ## When to Use<a name="section1269212236329"></a>
 

en/application-dev/media/audio-playback.md

-# Development Guidelines on Audio Playback
+# Audio Playback Development
 
 ## When to Use
 

en/application-dev/media/audio-recorder.md

-# Development Guidelines on Audio Recording<a name="EN-US_TOPIC_0000001163844398"></a>
+# Audio Recording Development<a name="EN-US_TOPIC_0000001163844398"></a>
 
 ## When to Use<a name="section910413166166"></a>