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

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

Index: client/dom/generated/src/frog/SVGLengthList.dart
diff --git a/client/dom/generated/src/frog/SVGLengthList.dart b/client/dom/generated/src/frog/SVGLengthList.dart
index aef862714a33b8f6f2f6d0305fec3a13636fbbe8..75fd5b012a6cf926d0d2e8ea0002828b989707f6 100644
--- a/client/dom/generated/src/frog/SVGLengthList.dart
+++ b/client/dom/generated/src/frog/SVGLengthList.dart
@@ -1,19 +1,19 @@
 
-class SVGLengthListJs extends DOMTypeJs implements SVGLengthList native "*SVGLengthList" {
+class _SVGLengthListJs extends _DOMTypeJs implements SVGLengthList native "*SVGLengthList" {
 
   int get numberOfItems() native "return this.numberOfItems;";
 
-  SVGLengthJs appendItem(SVGLengthJs item) native;
+  _SVGLengthJs appendItem(_SVGLengthJs item) native;
 
   void clear() native;
 
-  SVGLengthJs getItem(int index) native;
+  _SVGLengthJs getItem(int index) native;
 
-  SVGLengthJs initialize(SVGLengthJs item) native;
+  _SVGLengthJs initialize(_SVGLengthJs item) native;
 
-  SVGLengthJs insertItemBefore(SVGLengthJs item, int index) native;
+  _SVGLengthJs insertItemBefore(_SVGLengthJs item, int index) native;
 
-  SVGLengthJs removeItem(int index) native;
+  _SVGLengthJs removeItem(int index) native;
 
-  SVGLengthJs replaceItem(SVGLengthJs item, int index) native;
+  _SVGLengthJs replaceItem(_SVGLengthJs item, int index) native;
 }