This doc patch (master hash
66bc9d2d3e) was decided to be too
significant for backpatching, so reverted in all but master. Also fix
SGML file header comment in master.
Reported-by: Peter Eisentraut
Discussion: https://postgr.es/m/
c6304b19-6ff7-f3af-0148-
cf7aa7e2fbfd@enterprisedb.com
Backpatch-through: 11