Make dart:dom implementation types private so they don't muddle the docs.

client/dom/generated/src/frog/AudioBufferSourceNode.dart

 
-class AudioBufferSourceNodeJs extends AudioSourceNodeJs implements AudioBufferSourceNode native "*AudioBufferSourceNode" {
+class _AudioBufferSourceNodeJs extends _AudioSourceNodeJs implements AudioBufferSourceNode native "*AudioBufferSourceNode" {
 
-  AudioBufferJs get buffer() native "return this.buffer;";
+  _AudioBufferJs get buffer() native "return this.buffer;";
 
-  void set buffer(AudioBufferJs value) native "this.buffer = value;";
+  void set buffer(_AudioBufferJs value) native "this.buffer = value;";
 
-  AudioGainJs get gain() native "return this.gain;";
+  _AudioGainJs get gain() native "return this.gain;";
 
   bool get loop() native "return this.loop;";
 
   void set loop(bool value) native "this.loop = value;";
 
   bool get looping() native "return this.looping;";
 
   void set looping(bool value) native "this.looping = value;";
 
-  AudioParamJs get playbackRate() native "return this.playbackRate;";
+  _AudioParamJs get playbackRate() native "return this.playbackRate;";
 
   void noteGrainOn(num when, num grainOffset, num grainDuration) native;
 
   void noteOff(num when) native;
 
   void noteOn(num when) native;
 }