message: [devtools/x] Add `errmap` extension to ignored whitespace file extensions
  Exclude files with the `errmap` file extension from having whitespace lints
  run on them.
  Closes:
diff: @@ -98,6 +98,9 @@ fn skip_whitespace_checks<'l>(file: &FileContext<'l>) -> RunStatus<'l> {
  Some("exp") => {
  return RunStatus::Skipped(SkipReason::UnsupportedExtension(file.extension()))
  }
  + Some("errmap") => {
  + return RunStatus::Skipped(SkipReason::UnsupportedExtension(file.extension()))
  + }
  _ => (),
  }
  