README: make the link to the OpenSSL 3.0 Wiki page more prominent

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13164)

README.md

@@ -114,8 +114,7 @@ document.
  * [NOTES-Valgrind.md](NOTES-Valgrind.md)
 
 Specific notes on upgrading to OpenSSL 3.0 from previous versions, as well as
-known issues are available on the OpenSSL
-[wiki](https://wiki.openssl.org/index.php/OpenSSL_3.0).
+known issues are available on the [OpenSSL 3.0 Wiki] page.
 
 Documentation
 =============
@@ -194,6 +193,10 @@ All rights reserved.
     <https://wiki.openssl.org>
     "OpenSSL Wiki"
 
+[OpenSSL 3.0 Wiki]:
+    <https://wiki.openssl.org/index.php/OpenSSL_3.0>
+    "OpenSSL 3.0 Wiki"
+
 [RFC 8446]:
      <https://tools.ietf.org/html/rfc8446>