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/utils/time/combocid.c

@@ -253,7 +253,7 @@ GetComboCommandId(CommandId cmin, CommandId cmax)
 	key.cmin = cmin;
 	key.cmax = cmax;
 	entry = (ComboCidEntry) hash_search(comboHash,
-										(void *) &key,
+										&key,
 										HASH_ENTER,
 										&found);