Add more use of psprintf()

contrib/dblink/dblink.c

contrib/hstore/hstore_io.c

contrib/pageinspect/btreefuncs.c

contrib/pgstattuple/pgstatindex.c

doc/src/sgml/xtypes.sgml

src/backend/access/transam/multixact.c

src/backend/commands/define.c

src/backend/optimizer/plan/subselect.c

src/backend/parser/parse_type.c

src/backend/storage/smgr/md.c

src/backend/utils/adt/date.c

src/backend/utils/adt/timestamp.c

src/backend/utils/fmgr/funcapi.c

src/test/regress/regress.c

src/tutorial/complex.c