doc: Remove link to JSON support in the SQL specification

The link used in the documentation is dead, and the only options to have
an access to this part of the SQL specification are not free.  Like any
other books referred, just remove the link to keep some neutrality but
keep its reference.

Reported-by: Erik Rijkers
Discussion: https://postgr.es/m/989abd7d-af30-ab52-1201-bf0b4f33b872@xs4all.nl
Backpatch-through: 12

diff --git a/doc/src/sgml/biblio.sgml b/doc/src/sgml/biblio.sgml
index 8dddbf5f76880c7b0cad4fb6bdffec7fd8c542d0..912f3b1e740f5dd17fefc6492835da166e079141 100644 (file)
--- a/doc/src/sgml/biblio.sgml
+++ b/doc/src/sgml/biblio.sgml
@@ -137,7 +137,7 @@
    </biblioentry>
 
    <biblioentry id="sqltr-19075-6">
-    <title><ulink url="https://standards.iso.org/ittf/PubliclyAvailableStandards/c067367_ISO_IEC_TR_19075-6_2017.zip">SQL Technical Report</ulink></title>
+    <title>SQL Technical Report</title>
     <subtitle>Part 6: SQL support for JavaScript Object
       Notation (JSON)</subtitle>
     <edition>First Edition</edition>