Make xrefs to tables instead of assuming they appear below

doc/src/sgml/func.sgml

@@ -9616,7 +9616,7 @@ table2-mapping
  </sect1>
 
  <sect1 id="functions-json">
-  <title>JSON functions</title>
+  <title>JSON Functions</title>
 
   <indexterm zone="datatype-json">
     <primary>JSON</primary>
@@ -9624,8 +9624,8 @@ table2-mapping
   </indexterm>
 
   <para>
-    This section describes the functions that are available for creating
-    JSON (see <xref linkend="datatype-json">) data.
+   <xref linkend="functions-json-table"> shows the functions that are available
+   for creating JSON (see <xref linkend="datatype-json">) data.
   </para>
 
   <table id="functions-json-table">

doc/src/sgml/plpgsql.sgml

@@ -2601,7 +2601,8 @@ GET STACKED DIAGNOSTICS <replaceable>variable</replaceable> = <replaceable>item<
      Each <replaceable>item</replaceable> is a key word identifying a status
      value to be assigned to the specified variable (which should be
      of the right data type to receive it).  The currently available
-     status items are:
+     status items are shown in <xref linkend="plpgsql-exception-diagnostics-values">.
+    </para>
 
      <table id="plpgsql-exception-diagnostics-values">
       <title>Error diagnostics values</title>
@@ -2642,7 +2643,6 @@ GET STACKED DIAGNOSTICS <replaceable>variable</replaceable> = <replaceable>item<
        </tbody>
       </tgroup>
      </table>
-    </para>
 
     <para>
      If the exception did not set a value for an item, an empty string