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

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

Index: client/dom/generated/src/frog/SVGTextPositioningElement.dart
diff --git a/client/dom/generated/src/frog/SVGTextPositioningElement.dart b/client/dom/generated/src/frog/SVGTextPositioningElement.dart
index 7df3154e82f72080f7072d6ddf21a704dd6c8305..a6efc872ce10f06c1312c8a655d4dcfb9edabc6b 100644
--- a/client/dom/generated/src/frog/SVGTextPositioningElement.dart
+++ b/client/dom/generated/src/frog/SVGTextPositioningElement.dart
@@ -1,13 +1,13 @@
 
-class SVGTextPositioningElementJs extends SVGTextContentElementJs implements SVGTextPositioningElement native "*SVGTextPositioningElement" {
+class _SVGTextPositioningElementJs extends _SVGTextContentElementJs implements SVGTextPositioningElement native "*SVGTextPositioningElement" {
 
-  SVGAnimatedLengthListJs get dx() native "return this.dx;";
+  _SVGAnimatedLengthListJs get dx() native "return this.dx;";
 
-  SVGAnimatedLengthListJs get dy() native "return this.dy;";
+  _SVGAnimatedLengthListJs get dy() native "return this.dy;";
 
-  SVGAnimatedNumberListJs get rotate() native "return this.rotate;";
+  _SVGAnimatedNumberListJs get rotate() native "return this.rotate;";
 
-  SVGAnimatedLengthListJs get x() native "return this.x;";
+  _SVGAnimatedLengthListJs get x() native "return this.x;";
 
-  SVGAnimatedLengthListJs get y() native "return this.y;";
+  _SVGAnimatedLengthListJs get y() native "return this.y;";
 }