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

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

 
-class SVGFEMergeElementJs extends SVGElementJs implements SVGFEMergeElement native "*SVGFEMergeElement" {
+class _SVGFEMergeElementJs extends _SVGElementJs implements SVGFEMergeElement native "*SVGFEMergeElement" {
 
   // From SVGFilterPrimitiveStandardAttributes
 
-  SVGAnimatedLengthJs get height() native "return this.height;";
+  _SVGAnimatedLengthJs get height() native "return this.height;";
 
-  SVGAnimatedStringJs get result() native "return this.result;";
+  _SVGAnimatedStringJs get result() native "return this.result;";
 
-  SVGAnimatedLengthJs get width() native "return this.width;";
+  _SVGAnimatedLengthJs get width() native "return this.width;";
 
-  SVGAnimatedLengthJs get x() native "return this.x;";
+  _SVGAnimatedLengthJs get x() native "return this.x;";
 
-  SVGAnimatedLengthJs get y() native "return this.y;";
+  _SVGAnimatedLengthJs get y() native "return this.y;";
 
   // From SVGStylable
 
-  SVGAnimatedStringJs get className() native "return this.className;";
+  _SVGAnimatedStringJs get className() native "return this.className;";
 
-  CSSStyleDeclarationJs get style() native "return this.style;";
+  _CSSStyleDeclarationJs get style() native "return this.style;";
 
-  CSSValueJs getPresentationAttribute(String name) native;
+  _CSSValueJs getPresentationAttribute(String name) native;
 }