'Moved all documentation from old .dartdoc files.'

tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   factory $CLASSNAME() => _$(CLASSNAME)FactoryProvider.createDocumentFragment();
 
   factory $CLASSNAME.html(String html) =>
@@ skipping 41 matching lines @@
     this.nodes.clear();
 
     final e = new Element.tag("div");
     e.innerHtml = value;
 
     // Copy list first since we don't want liveness during iteration.
     List nodes = new List.from(e.nodes);
     this.nodes.addAll(nodes);
   }
 
+  /**
+   * Adds the specified element after the last child of this
+   * document fragment.
+   */
   void append(Element element) {
     this.children.add(element);
   }
 
+  /**
+   * Adds the specified text as a text node after the last child of this
+   * document fragment.
+   */
   void appendText(String text) {
     this.nodes.add(new Text(text));
   }
 
+
+  /**
+   * Parses the specified text as HTML and adds the resulting node after the
+   * last child of this document fragment.
+   */
   void appendHtml(String text) {
     this.nodes.add(new DocumentFragment.html(text));
   }
 
 $!MEMBERS
 }