56c6be57af
RAISE accepts either = or := in the USING clause, so fix the syntax synopsis to show that. Rearrange and wordsmith the descriptions of the different syntax variants, in hopes of improving clarity. Igor Gnatyuk, reviewed by Jian He and Laurenz Albe; minor additional wordsmithing by me Discussion: https://postgr.es/m/CAEu6iLvhF5sdGeat2x4_L0FvWW_SiN--ma8ya7CZd-oJoV+yqQ@mail.gmail.com