message: fix clang reference string in check_format.py
diff: @@ -191,7 +191,7 @@ def checkTools():
  "users".format(CLANG_FORMAT_PATH))
  else:
  error_messages.append(
  - "Command {} not found. If you have clang-format in version 7.x.x "
  + "Command {} not found. If you have clang-format in version 8.x.x "
  "installed, but the binary name is different or it's not available in "
  "PATH, please use CLANG_FORMAT environment variable to specify the path. "
  "Examples:\n"
  