remove commented-out debug printf from strstr

this was leftover from before the initial commit.

src/string/strstr.c

@@ -108,7 +108,6 @@ static char *twoway_strstr(const unsigned char *h, const unsigned char *n)
 		/* Check last byte first; advance by shift on mismatch */
 		if (BITOP(byteset, h[l-1], &)) {
 			k = l-shift[h[l-1]];
-			//printf("adv by %zu (on %c) at [%s] (%zu;l=%zu)\n", k, h[l-1], h, shift[h[l-1]], l);
 			if (k) {
 				if (mem && k < p) k = l-p;
 				h += k;