code: public static int getStartWeekOfMonth (@Nonnull final LocalDateTime aDT, @Nonnull final Locale aLocale)
    {
      return getWeekOfWeekBasedYear (aDT.withDayOfMonth (1), aLocale);
    }
docs: Get the start--week number for the passed year and month.
  
  @param aDT
  The object to use year and month from.
  @param aLocale
  Locale to use. May not be <code>null</code>.
  @return the start week number.