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

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

 
-class HTMLTableRowElementJs extends HTMLElementJs implements HTMLTableRowElement native "*HTMLTableRowElement" {
+class _HTMLTableRowElementJs extends _HTMLElementJs implements HTMLTableRowElement native "*HTMLTableRowElement" {
 
   String get align() native "return this.align;";
 
   void set align(String value) native "this.align = value;";
 
   String get bgColor() native "return this.bgColor;";
 
   void set bgColor(String value) native "this.bgColor = value;";
 
-  HTMLCollectionJs get cells() native "return this.cells;";
+  _HTMLCollectionJs get cells() native "return this.cells;";
 
   String get ch() native "return this.ch;";
 
   void set ch(String value) native "this.ch = value;";
 
   String get chOff() native "return this.chOff;";
 
   void set chOff(String value) native "this.chOff = value;";
 
   int get rowIndex() native "return this.rowIndex;";
 
   int get sectionRowIndex() native "return this.sectionRowIndex;";
 
   String get vAlign() native "return this.vAlign;";
 
   void set vAlign(String value) native "this.vAlign = value;";
 
   void deleteCell(int index) native;
 
-  HTMLElementJs insertCell(int index) native;
+  _HTMLElementJs insertCell(int index) native;
 }