pg-sys: add catalog/heap.h bindings for PG18 (#2150)

Closes #2146

Signed-off-by: Charalampos Mitrodimas <[email protected]>

Author: charmitro

pgrx-pg-sys/include/pg18.h

@@ -41,6 +41,7 @@
 #include "access/xlogutils.h"
 #include "catalog/catalog.h"
 #include "catalog/dependency.h"
+#include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
 #include "catalog/namespace.h"