first pass at cleaning up include files

src/backend/catalog/Makefile

src/backend/catalog/catalog.c

src/backend/catalog/heap.c

src/backend/catalog/index.c

src/backend/catalog/indexing.c

src/backend/catalog/pg_aggregate.c

src/backend/catalog/pg_operator.c

src/backend/catalog/pg_proc.c

src/backend/catalog/pg_type.c