message: Small doc update.
diff: @@ -257,7 +257,8 @@ bool IndexMain_DoParse(Config* config,
  import_manager, cache_manager, indexer, request->is_interactive,
  entry, request->contents);
  - // Don't bother sending an IdMap request if there are no responses.
  + // Don't bother sending an IdMap request if there are no responses. This
  + // avoids a lock.
  if (responses.empty())
  return false;
  