Update charted to 0.4.8 and roll

packages/args/lib/src/help_command.dart

Index: packages/args/lib/src/help_command.dart
diff --git a/packages/args/lib/src/help_command.dart b/packages/args/lib/src/help_command.dart
index f477b4740e630160700eb34eaee325a9af791726..104327c9a05424287b44f816836606e1c66f7867 100644
--- a/packages/args/lib/src/help_command.dart
+++ b/packages/args/lib/src/help_command.dart
@@ -2,30 +2,28 @@
 // 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.
 
-library args.help_command;
-
 import '../command_runner.dart';
 
 /// The built-in help command that's added to every [CommandRunner].
 ///
 /// This command displays help information for the various subcommands.
-class HelpCommand extends Command {
+class HelpCommand<T> extends Command<T> {
   final name = "help";
   String get description =>
       "Display help information for ${runner.executableName}.";
   String get invocation => "${runner.executableName} help [command]";
 
-  void run() {
+  T run() {
     // Show the default help if no command was specified.
     if (argResults.rest.isEmpty) {
       runner.printUsage();
-      return;
+      return null;
     }
 
     // Walk the command tree to show help for the selected command or
     // subcommand.
     var commands = runner.commands;
-    var command = null;
+    Command command;
     var commandString = runner.executableName;
 
     for (var name in argResults.rest) {
@@ -49,5 +47,6 @@ class HelpCommand extends Command {
     }
 
     command.printUsage();
+    return null;
   }
 }