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

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

Index: client/dom/generated/src/frog/SVGFEMergeElement.dart
diff --git a/client/dom/generated/src/frog/SVGFEMergeElement.dart b/client/dom/generated/src/frog/SVGFEMergeElement.dart
index 4ff2aa5a3c9f7a3dda231295019c7857cefe9358..2c51cd1058449416c1e307eabc365b76839df602 100644
--- a/client/dom/generated/src/frog/SVGFEMergeElement.dart
+++ b/client/dom/generated/src/frog/SVGFEMergeElement.dart
@@ -1,23 +1,23 @@
 
-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;
 }