curl.1: fix trivial typo

docs/curl.1

@@ -177,7 +177,7 @@ considered insecure.
 (SSL) Forces curl to use SSL version 3 when negotiating with a remote SSL
 server. Sometimes curl is built without SSLv3 support.
 .IP "-4, --ipv4"
-Tis option tells curl to resolve names to IPv4 addresses only, and not for
+This option tells curl to resolve names to IPv4 addresses only, and not for
 example try IPv6.
 .IP "-6, --ipv6"
 This option tells curl to resolve names to IPv6 addresses only, and not for