Update shared_buffer comment in postgresql.conf.

src/backend/utils/misc/postgresql.conf.sample

@@ -47,7 +47,7 @@
 #
 #	Shared Memory Size
 #
-#shared_buffers = 64		# at least 2*max_connections, min 16, 8KB each
+#shared_buffers = 64		# min 2*max_connections or 16, 8KB each
 #max_fsm_relations = 1000	# min 10, fsm is free space map, ~40 bytes
 #max_fsm_pages = 10000		# min 1000, fsm is free space map, ~6 bytes
 #max_locks_per_transaction = 64	# min 10