Fix comment in procarray.c

The description of GlobalVisDataRels was missing, GlobalVisCatalogRels
being mentioned instead.

Author: Jim Nasby
Discussion: https://postgr.es/m/8e06c883-2858-1fd4-07c5-560c28b08dcd@amazon.com

src/backend/storage/ipc/procarray.c

@@ -146,7 +146,7 @@ typedef struct ProcArrayStruct
  *    I.e. the difference to GlobalVisSharedRels is that
  *    snapshot in other databases are ignored.
  *
- * 3) GlobalVisCatalogRels, which only considers an XID's
+ * 3) GlobalVisDataRels, which only considers an XID's
  *    effects visible-to-everyone if neither snapshots in the current
  *    database, nor a replication slot's xmin consider XID as running.
  *