doc: fix v14.x link maintaining openssl guide

Author: RafaelGSS

doc/contributing/maintaining-openssl.md

@@ -9,7 +9,8 @@ currently need to generate four PRs as follows:
   below for OpenSSL 3.x.x.
 * a PR for 16.x following the instructions in the v16.x-staging version
   of this guide.
-* a PR for 14.x following the instructions in the v14.x-staging version
+* a PR for 14.x following the instructions in the [v14.x-staging version]
+  (https://github.com/nodejs/node/blob/v14.x-staging/doc/guides/maintaining-openssl.md)
   of this guide.
 
 ## Use of the quictls/openssl fork