doc/1.17: fix two dead rfc links

Updates #44513

Change-Id: Ia0c6b48bde2719f3a99cb216b6166d82159198d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/336930
Trust: Alberto Donizetti <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: ALTree

doc/go1.17.html

@@ -886,8 +886,8 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   <dd>
     <p><!-- CL 272668 -->
       The new method <a href="/pkg/net/#IP.IsPrivate"><code>IP.IsPrivate</code></a> reports whether an address is
-      a private IPv4 address according to <a href="http://tools.ietf.org/html/rfc1918">RFC 1918</a>
-      or a local IPv6 address according <a href="http://tools.ietf.org/html/rfc4193">RFC 4193</a>.
+      a private IPv4 address according to <a href="https://datatracker.ietf.org/doc/rfc1918">RFC 1918</a>
+      or a local IPv6 address according <a href="https://datatracker.ietf.org/doc/rfc4193">RFC 4193</a>.
     </p>
 
     <p><!-- CL 301709 -->