Fix git hooks on Windows

tools/githooks/lib/src/messages.dart

@@ -14,6 +14,6 @@ void printGclientSyncReminder(String command) {
   final String postfix = io.stdout.supportsAnsiEscapes ? _reset : '';
   io.stderr.writeln('$command: The engine source tree has been updated.');
   io.stderr.writeln(
-    '\n${prefix}You man need to run "gclient sync -D"$postfix\n',
+    '\n${prefix}You may need to run "gclient sync -D"$postfix\n',
   );
 }

tools/githooks/post-checkout

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env vpython3
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

tools/githooks/post-merge

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env vpython3
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

tools/githooks/pre-push

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env vpython3
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

tools/githooks/pre-rebase

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env vpython3
 # Copyright 2013 The Flutter Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.