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

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

 
-class HTMLTableColElementJs extends HTMLElementJs implements HTMLTableColElement native "*HTMLTableColElement" {
+class _HTMLTableColElementJs extends _HTMLElementJs implements HTMLTableColElement native "*HTMLTableColElement" {
 
   String get align() native "return this.align;";
 
   void set align(String value) native "this.align = value;";
 
   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 span() native "return this.span;";
 
   void set span(int value) native "this.span = value;";
 
   String get vAlign() native "return this.vAlign;";
 
   void set vAlign(String value) native "this.vAlign = value;";
 
   String get width() native "return this.width;";
 
   void set width(String value) native "this.width = value;";
 }