Start to implicitly include \n in rc_header_format.

grit/format/rc_header.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 '''Item formatters for RC headers.
 '''
 
 from grit import exception
 from grit import util
@@ skipping 35 matching lines @@
   '''
   from grit.node import message
   tids = GetIds(root)
 
   if output_all_resource_defines:
     items = root.Preorder()
   else:
     items = root.ActiveDescendants()
 
   if not rc_header_format:
-    rc_header_format = "#define {textual_id} {numeric_id}\n"
+    rc_header_format = "#define {textual_id} {numeric_id}"
+  rc_header_format += "\n"
   seen = set()
   for item in items:
     if not isinstance(item, message.MessageNode):
       with item:
         for tid in item.GetTextualIds():
           if tid in tids and tid not in seen:
             seen.add(tid)
             yield rc_header_format.format(textual_id=tid,numeric_id=tids[tid])
 
   # Temporarily mimic old behavior: MessageNodes were only output if active,
@@ skipping 127 matching lines @@
 
       if id < 101:
         print ('WARNING: Numeric resource IDs should be greater than 100 to\n'
                'avoid conflicts with system-defined resource IDs.')
 
       ids[id] = tid
       tids[tid] = id
       id_reasons[id] = reason
 
   return tids