Fix typo

src/lib/libc/hash/sha1.3

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sha1.3,v 1.5 1997/07/15 01:54:23 millert Exp $
+.\"	$OpenBSD: sha1.3,v 1.6 1997/07/17 05:33:16 millert Exp $
 .\"
 .\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 .\" All rights reserved.
@@ -59,7 +59,7 @@
 .Ft "char *"
 .Fn SHA1Data "u_char *data" "u_int len" "char *buf"
 .Sh DESCRIPTION
-The SHA1 functions implement then NIST Secure Hash Algorithm (SHA-1),
+The SHA1 functions implement the NIST Secure Hash Algorithm (SHA-1),
 FIPS PUB 180-1.  SHA-1 is used to generate a condensed representation
 of a message called a message digest.  The algorithm takes a
 message less than 2^64 bits as input and produces a 160-bit digest