Update debug help (#333)

Author: grouma

webdev/README.md

@@ -45,19 +45,19 @@ Usage: webdev serve [arguments] [<directory>[:<port>]]...
                                   (loses current state)
                                   refresh: Performs a full page refresh.
                                   [restart, refresh]
+
     --chrome-debug-port           Specify which port the Chrome debugger is
                                   listening on. If used with launch-in-chrome
                                   Chrome will be started with the debugger
                                   listening on this port.
 
-    --[no-]debug                  Enable the launching of DevTools (Alt + D).
-                                  Must use with either --launch-in-chrome or
-                                  --chrome-debug-port.
+    --[no-]debug                  Enable the launching of DevTools (Alt + D /
+                                  Option + D). This also enables
+                                  --launch-in-chrome.
 
     --hostname                    Specify the hostname to serve on.
                                   (defaults to "localhost")
 
-
     --[no-]launch-in-chrome       Automatically launches your application in
                                   Chrome with the debug port open. Use
                                   chrome-debug-port to specify a specific port

webdev/lib/src/command/serve_command.dart

@@ -63,9 +63,8 @@ refresh: Performs a full page refresh.
               'If used with $launchInChromeFlag Chrome will be started with the'
               ' debugger listening on this port.')
       ..addFlag(debugFlag,
-          help: 'Enable the launching of DevTools (Alt + D). '
-              'Must use with either --$launchInChromeFlag or '
-              '--$chromeDebugPortFlag.')
+          help: 'Enable the launching of DevTools (Alt + D / Option + D). '
+              'This also enables --$launchInChromeFlag.')
       ..addOption(hostnameFlag,
           help: 'Specify the hostname to serve on.', defaultsTo: 'localhost')
       ..addFlag(hotRestartFlag,