Change mojo application name to {name}.mojo

mojo/services/public/interfaces/content_handler/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//mojo/public/tools/bindings/mojom.gni")
 
-# GYP version: mojo/mojo_services.gypi:mojo_content_handler_bindings
 mojom("content_handler") {
   sources = [
     "content_handler.mojom",
   ]
 
   deps = [
     "//mojo/public/interfaces/application",
     "//mojo/services/public/interfaces/network",
   ]
 }