Thread: pgsql: Convert planner's AggInfo and AggTransInfo structs to proper Nod

Convert planner's AggInfo and AggTransInfo structs to proper Nodes.

This is mostly just to get outfuncs.c support for them, so that
the agginfos and aggtransinfos lists can be dumped when dumping
the contents of PlannerInfo.

While here, improve some related comments; notably, clean up
obsolete comments left over from when preprocess_minmax_aggregates
had to make its own scan of the query tree.

Discussion: https://postgr.es/m/742479.1658160504@sss.pgh.pa.us

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/d6a3aeb9a37bdbb5aa8ed03a9f95e2b1a1b44ba7

Modified Files
--------------
src/backend/optimizer/plan/planagg.c | 20 ++++++++---------
src/backend/optimizer/prep/prepagg.c | 16 ++++++++------
src/include/nodes/pathnodes.h        | 42 ++++++++++++++++++++++--------------
3 files changed, 45 insertions(+), 33 deletions(-)