Doc: update libpq's documentation for PQfn().
Mention specifically that you can't call aggregates, window functions,
or procedures this way (the inability to call SRFs was already
mentioned).
Also, the claim that PQfn doesn't support NULL arguments or results
has been a lie since we invented protocol 3.0. Not sure why this
text was never updated for that, but do it now.
Discussion: https://postgr.es/m/2039442.1615317309@sss.pgh.pa.us
Branch
------
REL_11_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/d25997f898dd8c36fc7acad3f22366f18b548200
Modified Files
--------------
doc/src/sgml/libpq.sgml | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)