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

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

 
-class SVGGradientElementJs extends SVGElementJs implements SVGGradientElement native "*SVGGradientElement" {
+class _SVGGradientElementJs extends _SVGElementJs implements SVGGradientElement native "*SVGGradientElement" {
 
   static final int SVG_SPREADMETHOD_PAD = 1;
 
   static final int SVG_SPREADMETHOD_REFLECT = 2;
 
   static final int SVG_SPREADMETHOD_REPEAT = 3;
 
   static final int SVG_SPREADMETHOD_UNKNOWN = 0;
 
-  SVGAnimatedTransformListJs get gradientTransform() native "return this.gradientTransform;";
+  _SVGAnimatedTransformListJs get gradientTransform() native "return this.gradientTransform;";
 
-  SVGAnimatedEnumerationJs get gradientUnits() native "return this.gradientUnits;";
+  _SVGAnimatedEnumerationJs get gradientUnits() native "return this.gradientUnits;";
 
-  SVGAnimatedEnumerationJs get spreadMethod() native "return this.spreadMethod;";
+  _SVGAnimatedEnumerationJs get spreadMethod() native "return this.spreadMethod;";
 
   // From SVGURIReference
 
-  SVGAnimatedStringJs get href() native "return this.href;";
+  _SVGAnimatedStringJs get href() native "return this.href;";
 
   // From SVGExternalResourcesRequired
 
-  SVGAnimatedBooleanJs get externalResourcesRequired() native "return this.externalResourcesRequired;";
+  _SVGAnimatedBooleanJs get externalResourcesRequired() native "return this.externalResourcesRequired;";
 
   // 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;
 }