pgsql: Rename SetSingleFuncCall() to InitMaterializedSRF()

Rename SetSingleFuncCall() to InitMaterializedSRF()

Per discussion, the existing routine name able to initialize a SRF
function with materialize mode is unpopular, so rename it. Equally, the
flags of this function are renamed, as of:
- SRF_SINGLE_USE_EXPECTED -> MAT_SRF_USE_EXPECTED_DESC
- SRF_SINGLE_BLESS -> MAT_SRF_BLESS
The previous function and flags introduced in 9e98583 are kept around
for compatibility purposes, so as any extension code already compiled
with v15 continues to work as-is. The declarations introduced here for
compatibility will be removed from HEAD in a follow-up commit.

The new names have been suggested by Andres Freund and Melanie
Plageman.

Discussion: https://postgr.es/m/20221013194820.ciktb2sbbpw7cljm@awork3.anarazel.de
Backpatch-through: 15

Branch
------
REL_15_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/f2f7e509e6a96329805ecaf30fb64ba4c7f4b0d2

Modified Files
--------------
contrib/amcheck/verify_heapam.c | 2 +-
contrib/dblink/dblink.c | 2 +-
contrib/pageinspect/brinfuncs.c | 2 +-
contrib/pageinspect/gistfuncs.c | 4 ++--
contrib/pg_stat_statements/pg_stat_statements.c | 2 +-
contrib/pg_walinspect/pg_walinspect.c | 4 ++--
contrib/pgrowlocks/pgrowlocks.c | 2 +-
contrib/postgres_fdw/connection.c | 2 +-
contrib/xml2/xpath.c | 2 +-
src/backend/access/transam/rmgr.c | 2 +-
src/backend/access/transam/xlogprefetcher.c | 2 +-
src/backend/commands/event_trigger.c | 4 ++--
src/backend/commands/extension.c | 6 +++---
src/backend/commands/prepare.c | 2 +-
src/backend/foreign/foreign.c | 2 +-
src/backend/replication/logical/launcher.c | 2 +-
src/backend/replication/logical/logicalfuncs.c | 2 +-
src/backend/replication/logical/origin.c | 2 +-
src/backend/replication/slotfuncs.c | 2 +-
src/backend/replication/walsender.c | 2 +-
src/backend/storage/ipc/shmem.c | 2 +-
src/backend/utils/adt/datetime.c | 2 +-
src/backend/utils/adt/genfile.c | 4 ++--
src/backend/utils/adt/hbafuncs.c | 4 ++--
src/backend/utils/adt/jsonfuncs.c | 9 ++++-----
src/backend/utils/adt/mcxtfuncs.c | 2 +-
src/backend/utils/adt/misc.c | 2 +-
src/backend/utils/adt/pgstatfuncs.c | 6 +++---
src/backend/utils/adt/varlena.c | 2 +-
src/backend/utils/fmgr/README | 2 +-
src/backend/utils/fmgr/funcapi.c | 23 ++++++++++++++++-------
src/backend/utils/misc/guc.c | 2 +-
src/backend/utils/misc/pg_config.c | 2 +-
src/backend/utils/mmgr/portalmem.c | 2 +-
src/include/funcapi.h | 14 ++++++++++----
35 files changed, 71 insertions(+), 57 deletions(-)