Typo fix in ipc_message_util help text.

tools/ipc_fuzzer/mutate/message_util.cc

 // 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.
 
 #include <limits.h>
 #include <stdlib.h>
 #include <iostream>
 #include <string>
 #include <vector>
 
@@ skipping 34 matching lines @@
     "output messages after |n|th message in file (inclusive).";
 
 void usage() {
   std::cerr << "ipc_message_util: Concatenate all |infile| message files and "
             << "copy a subset of the result to |outfile|.\n";
 
   std::cerr << "Usage:\n"
             << "  ipc_message_util"
             << " [--" << kStartSwitch << "=n]"
             << " [--" << kEndSwitch << "=m]"
-            << " [--" << kInSwitch << "=i,j,...]]"
+            << " [--" << kInSwitch << "=i[,j,...]]"
             << " [--" << kRegexpSwitch << "=x]"
             << " [--" << kInvertSwitch << "]"
             << " [--" << kDumpSwitch << "]"
             << " [--" << kHelpSwitch << "]"
             << " infile,infile,... [outfile]\n";
 
   std::cerr << "    --" << kStartSwitch << "  - " << kStartSwitchHelp << "\n"
             << "    --" << kEndSwitch << "    - " << kEndSwitchHelp << "\n"
             << "    --" << kInSwitch << "     - " << kInSwitchHelp << "\n"
             << "    --" << kRegexpSwitch << " - " << kRegexpSwitchHelp << "\n"
@@ skipping 105 matching lines @@
     }
   } else {
     if (!ipc_fuzzer::MessageFile::Write(
             base::FilePath(output_file_name), output_message_vector)) {
       return EXIT_FAILURE;
     }
   }
 
   return EXIT_SUCCESS;
 }