pgsql: doc: clarify that jsonb_path_match() returns an SQL boolean

doc: clarify that jsonb_path_match() returns an SQL boolean

Not a JSON boolean. Also clarify that other predicate check expressions
functions return a JSON boolean, not an SQL boolean.

Reported-by: jian he

Discussion: /messages/by-id/CACJufxH7tP1NXCHN1bUBXcEB=dv7-qE+ZjB3UxwK6Em+9Qzb9Q@mail.gmail.com

Backpatch-through: 17

Branch
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REL_17_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/7eff3138fc86cbea556c63a902fd3fcbf04bdf1d

Modified Files
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doc/src/sgml/func.sgml | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)