docs: @Nonnull
    public JSFormatter generatable (@Nonnull final Iterable <? extends IJSGeneratable> aCont)
    {
      boolean bFirst = true;
      for (final IJSGeneratable aItem : aCont)
      {
        if (bFirst)
          bFirst = false;
        else
          plain (',');
        generatable (aItem);
      }
      return this;
    }