BUG #16647: ts_lexize with dict_voikko no longer works as of PostgreSQL 13.0

The following bug has been logged on the website:

Bug reference:      16647
Logged by:          Matti Linnanvuori
Email address:      matti.linnanvuori@portalify.com
PostgreSQL version: 13.0
Operating system:   Red Hat Enterprise Linux 8.2
Description:

ts_lexize with dict_voikko no longer works as of PostgreSQL 13.0 but it
worked in PostgreSQL 12.4.
dnf install postgresql13
dnf install postgresql13-server
dnf install postgresql13-devel
dnf install libvoikko
dnf install malaga-suomi-voikko
wget
https://www.puimula.org/htp/testing/voikko-snapshot-v5/dict-morpho.zip
unzip dict-morpho.zip
mkdir /etc/voikko
mv 5 /etc/voikko
git clone https://github.com/MattiL/dict_voikko.git
cp -r dict_voikko /usr/pgsql-13/share/contrib
cd /usr/pgsql-13/share/contrib/dict_voikko
PATH="/usr/pgsql-13/bin:$PATH" make clean install USE_PGXS=1
PGSETUP_INITDB_OPTIONS=--locale=fi_FI.utf8
/usr/pgsql-13/bin/postgresql-13-setup initdb
createdb -E UTF8 test
CREATE EXTENSION dict_voikko;
CREATE TEXT SEARCH DICTIONARY voikko_stopwords (TEMPLATE = voikko_template,
StopWords = finnish);
CREATE TEXT SEARCH CONFIGURATION voikko (COPY = pg_catalog.finnish);
ALTER TEXT SEARCH CONFIGURATION voikko ALTER MAPPING FOR asciiword,
asciihword, hword_asciipart, word, hword, hword_part WITH voikko_stopwords,
finnish_stem;' tasks";
test=# select ts_lexize('voikko', 'kerrostalollekohan');
 ts_lexize 
-----------
 
(1 row)

PostgreSQL 12.4:
test=# select ts_lexize('voikko', 'kerrostalollekohan');
   ts_lexize   
---------------
 {kerros,talo}
(1 row)