message: check_format: Update error messages
  This updates error message for CLANG_FORMAT and bazelbuild/buildtools
  when these are not found.
diff: @@ -218,7 +218,7 @@ def checkTools():
  "users".format(CLANG_FORMAT_PATH))
  else:
  error_messages.append(
  - "Command {} not found. If you have clang-format in version 8.x.x "
  + "Command {} not found. If you have clang-format in version 9.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"
  @@ -238,13 +238,13 @@ def checkTools():
  "users".format(path))
  else:
  - error_messages.append(
  - "Command {} not found. If you have buildifier installed, but the binary "
  + error_messages.append("Command {} not found. If you have {} installed, but the binary "
  "name is different or it's not available in $GOPATH/bin, please use "
  "{} environment variable to specify the path. Example:\n"
  - " export {}=/opt/bin/buildifier\n"
  - "If you don't have buildifier installed, you can install it by:\n"
  - " go get -u github.com/bazelbuild/buildtools/{}".format(path, var, var, name))
  + " export {}=`which {}`\n"
  + "If you don't have {} installed, you can install it by:\n"
  + " go get -u github.com/bazelbuild/buildtools/{}".format(
  + path, name, var, var, name, name, name))
  checkBazelTool('buildifier', BUILDIFIER_PATH, 'BUILDIFIER_BIN')
  checkBazelTool('buildozer', BUILDOZER_PATH, 'BUILDOZER_BIN')
  