Change the output of unnamed constructors in our files.

pkg/docgen/lib/docgen.dart

 // Copyright (c) 2013, 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.
 
 /// **docgen** is a tool for creating machine readable representations of Dart
 /// code metadata, including: classes, members, comments and annotations.
 ///
 /// docgen is run on a `.dart` file or a directory containing `.dart` files.
 ///
 ///      $ dart docgen.dart [OPTIONS] [FILE/DIR]
@@ skipping 1484 matching lines @@
 
 /// Given a mirror, returns its qualified name, but following the conventions
 /// we're using in Dartdoc, which is that library names with dots in them
 /// have them replaced with hyphens.
 String docName(DeclarationMirror m) {
   if (m is LibraryMirror) {
     return m.qualifiedName.replaceAll('.','-');
   }
   var owner = m.owner;
   if (owner == null) return m.qualifiedName;
-  // For the unnamed constructor we just return the class name.
-  if (m.simpleName == '') return docName(owner);
-  return docName(owner) + '.' + m.simpleName;
+  var simpleName = m.simpleName;
+  if (m is MethodMirror && m.isConstructor) {
+    // We name constructors specially -- including the class name again and a
+    // "-" to separate the constructor from its name (if any).
+    simpleName = '${owner.simpleName}-$simpleName';
+  }
+  return docName(owner) + '.' + simpleName;
 }
 
 /// Remove statics from the map of inherited items before adding them.
 Map _filterStatics(Map items) {
   var result = {};
   items.forEach((name, item) {
     if (!item.isStatic) {
       result[name] = item;
     }
   });
   return result;
 }