Make an editorial pass over the 9.2 release notes.

A very large number of small improvements ...

doc/src/sgml/datatype.sgml

@@ -4196,7 +4196,9 @@ SET xmloption TO { DOCUMENT | CONTENT };
    </indexterm>
 
    <para>
-    The <type>json</type> data type can be used to store JSON data.  Such
+    The <type>json</type> data type can be used to store JSON (JavaScript
+    Object Notation) data, as specified in <ulink
+    url="http://www.ietf.org/rfc/rfc4627.txt">RFC 4627</ulink>.  Such
     data can also be stored as <type>text</type>, but the
     <type>json</type> data type has the advantage of checking that each
     stored value is a valid JSON value.  There are also related support

doc/src/sgml/func.sgml

@@ -9620,7 +9620,7 @@ table2-mapping
  <sect1 id="functions-json">
   <title>JSON Functions</title>
 
-  <indexterm zone="datatype-json">
+  <indexterm zone="functions-json">
     <primary>JSON</primary>
     <secondary>Functions and operators</secondary>
   </indexterm>