Remove useless casts to (void *) in hash_search() calls

Some of these appear to be leftovers from when hash_search() took a
char * argument (changed in 5999e78fc4).

Since after this there is some more horizontal space available, do
some light reformatting where suitable.

Reviewed-by: Corey Huinker <corey.huinker@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/fd9adf5d-b1aa-e82f-e4c7-263c30145807%40enterprisedb.com

src/backend/replication/pgoutput/pgoutput.c

@@ -2026,7 +2026,7 @@ get_rel_sync_entry(PGOutputData *data, Relation relation)
 
 	/* Find cached relation info, creating if not found */
 	entry = (RelationSyncEntry *) hash_search(RelationSyncCache,
-											  (void *) &relid,
+											  &relid,
 											  HASH_ENTER, &found);
 	Assert(entry != NULL);