Doc: Update ulinks to RFC documents to avoid redirect

The tools.ietf.org site has been decommissioned and replaced by a
number of sites serving various purposes.  Links to RFCs and BCPs
are now 301 redirected to their new respective IETF sites.  Since
this serves no purpose and only adds network overhead, update our
links to the new locations.

Backpatch to all supported versions.

Discussion: https://postgr.es/m/3C1CEA99-FCED-447D-9858-5A579B4C6687@yesql.se
Backpatch-through: v12

5 files changed, 6 insertions, 6 deletions

diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml
index 6c2f76537e9..a41c867a685 100644
--- a/doc/src/sgml/charset.sgml
+++ b/doc/src/sgml/charset.sgml
@@ -834,7 +834,7 @@ CREATE COLLATION german (provider = libc, locale = 'de_DE');
 
     See <ulink url="http://unicode.org/reports/tr35/tr35-collation.html">Unicode
     Technical Standard #35</ulink>
-    and <ulink url="https://tools.ietf.org/html/bcp47">BCP 47</ulink> for
+    and <ulink url="https://www.rfc-editor.org/info/bcp47">BCP 47</ulink> for
     details.  The list of possible collation types (<literal>co</literal>
     subtag) can be found in
     the <ulink url="https://github.com/unicode-org/cldr/blob/master/common/bcp47/collation.xml">CLDR
diff --git a/doc/src/sgml/client-auth.sgml b/doc/src/sgml/client-auth.sgml
index 246d8825a79..3e7a9efd8cc 100644
--- a/doc/src/sgml/client-auth.sgml
+++ b/doc/src/sgml/client-auth.sgml
@@ -1079,7 +1079,7 @@ omicron         bryanh                  guest1
       <para>
        The method <literal>scram-sha-256</literal> performs SCRAM-SHA-256
        authentication, as described in
-       <ulink url="https://tools.ietf.org/html/rfc7677">RFC 7677</ulink>.  It
+       <ulink url="https://datatracker.ietf.org/doc/html/rfc7677">RFC 7677</ulink>.  It
        is a challenge-response scheme that prevents password sniffing on
        untrusted connections and supports storing passwords on the server in a
        cryptographically hashed form that is thought to be secure.
@@ -1191,7 +1191,7 @@ omicron         bryanh                  guest1
    <para>
     <productname>GSSAPI</productname> is an industry-standard protocol
     for secure authentication defined in
-    <ulink url="https://tools.ietf.org/html/rfc2743">RFC 2743</ulink>.
+    <ulink url="https://datatracker.ietf.org/doc/html/rfc2743">RFC 2743</ulink>.
     <productname>PostgreSQL</productname>
     supports <productname>GSSAPI</productname> for authentication,
     communications encryption, or both.
diff --git a/doc/src/sgml/json.sgml b/doc/src/sgml/json.sgml
index 7ebc4c94b2e..97677c48761 100644
--- a/doc/src/sgml/json.sgml
+++ b/doc/src/sgml/json.sgml
@@ -13,7 +13,7 @@
 
  <para>
   JSON data types are for storing JSON (JavaScript Object Notation)
-  data, as specified in <ulink url="https://tools.ietf.org/html/rfc7159">RFC
+  data, as specified in <ulink url="https://datatracker.ietf.org/doc/html/rfc7159">RFC
   7159</ulink>. Such data can also be stored as <type>text</type>, but
   the JSON data types have the advantage of enforcing that each
   stored value is valid according to the JSON rules.  There are also
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 7f34755cd5d..cda4e8d98aa 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -798,7 +798,7 @@ PGPing PQping(const char *conninfo);
     connection parameters.  There are two accepted formats for these strings:
     plain keyword/value strings
     and URIs.  URIs generally follow
-    <ulink url="https://tools.ietf.org/html/rfc3986">RFC
+    <ulink url="https://datatracker.ietf.org/doc/html/rfc3986">RFC
     3986</ulink>, except that multi-host connection strings are allowed
     as further described below.
    </para>
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 8a0d6b196e2..75ad04c5010 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -2710,7 +2710,7 @@ lo_import 152801
           </indexterm>
           writes column values separated by commas, applying the quoting
           rules described in
-          <ulink url="https://tools.ietf.org/html/rfc4180">RFC 4180</ulink>.
+          <ulink url="https://datatracker.ietf.org/doc/html/rfc4180">RFC 4180</ulink>.
           This output is compatible with the CSV format of the server's
           <command>COPY</command> command.
           A header line with column names is generated unless