Updated the schema of the yaml output.

pkg/docgen/lib/src/io.dart

 library io;
 /// This is a helper library to make working with io easier.
 // TODO(janicejl): listDir, canonicalize, resolveLink, and linkExists are from
 // pub/lib/src/io.dart. If the io.dart file becomes a package, should remove
 // copy of the functions.
 
 import 'dart:collection';
 import 'dart:io';
-import 'package:path/path.dart' as path;
+import 'package:pathos/path.dart' as path;
 
 /// Lists the contents of [dir]. If [recursive] is `true`, lists subdirectory
 /// contents (defaults to `false`). If [includeHidden] is `true`, includes files
 /// and directories beginning with `.` (defaults to `false`).
 ///
 /// The returned paths are guaranteed to begin with [dir].
 List<String> listDir(String dir, {bool recursive: false,
     bool includeHidden: false}) {
   List<String> doList(String dir, Set<String> listedDirectories) {
     var contents = <String>[];
@@ skipping 122 matching lines @@
     seen.add(link);
     link = path.normalize(path.join(
         path.dirname(link), new Link(link).targetSync()));
   }
   return link;
 }
 
 /// Returns whether [link] exists on the file system. This will return `true`
 /// for any symlink, regardless of what it points at or whether it's broken.
 bool linkExists(String link) => new Link(link).existsSync();