top(8): use designated initializers for sorted_state[]

Also correct comments for individual state, duplicating the S* constants
descriptions from sys/proc.h [*].

Reviewed by:	kevans (previous version)
Noted by:	Mark Millard <marklmi@yahoo.com> [*]
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D40607

usr.bin/top/machine.c

@@ -1262,13 +1262,12 @@ compare_tid(const void *p1, const void *p2)
  */
 
 static const int sorted_state[] = {
-	0,	/* not used		*/
-	3,	/* sleep		*/
-	1,	/* ABANDONED (WAIT)	*/
-	6,	/* run			*/
-	5,	/* start		*/
-	2,	/* zombie		*/
-	4	/* stop			*/
+	[SIDL] =	3,	/* being created	*/
+	[SRUN] =	1,	/* running/runnable	*/
+	[SSLEEP] =	6,	/* sleeping		*/
+	[SSTOP] =	5,	/* stopped/suspended	*/
+	[SZOMB] =	2,	/* zombie		*/
+	[SWAIT] =	4,	/* intr			*/
 };