code: public boolean recordMappedIdGenerator() {
      if (!currentInfo.isMappedIdGenerator()) {
        currentInfo.setMappedIdGenerator(true);
        populated = true;
        return true;
      } else {
        return false;
      }
    }
docs: Records that the {@link JSDocInfo} being built should have its {@link
  JSDocInfo#isStableIdGenerator()} flag set to {@code true}.
  
  @return {@code true} if the stableIdGenerator flag was recorded and {@code false} if it was
  already recorded.