pgsql: doc: correct syntax of pgtrgm examples in older releases

doc: correct syntax of pgtrgm examples in older releases Reported-by: Liudmila Mantrova Discussion: https://postgr.es/m/[email protected] Backpatch-through: 9.6 and 10 only Branch -- REL9_6_STABLE Details --- https://git.postgresql.org/pg/commitdiff/

pgsql: doc: correct syntax of pgtrgm examples in older releases

doc: correct syntax of pgtrgm examples in older releases Reported-by: Liudmila Mantrova Discussion: https://postgr.es/m/[email protected] Backpatch-through: 9.6 and 10 only Branch -- REL_10_STABLE Details --- https://git.postgresql.org/pg/commitdiff/