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(-)