Because the lookup table (include/svtools/htmlkywd.hxx) is now lowercase.

Change-Id: Ica0606eb1546f74d2b651a70adee8117c956d4e2
Reviewed-on: https://gerrit.libreoffice.org/6193Reviewed-by: Thomas Arnhold <thomas@arnhold.org>
Tested-by: Thomas Arnhold <thomas@arnhold.org>