fdo#84938: replace SYMBOL_TYPE constants with enum

Change-Id: Ib3763f20d74c22e28d519a9ac47f6f3ab4e31f51
Reviewed-on: https://gerrit.libreoffice.org/11983
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>