doc: Add links to tables

Formal tables should generally have an xref in the text that points to
them.  Add them here.

doc/src/sgml/config.sgml

@@ -7663,11 +7663,12 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
      </para>
 
      <para>
-      Each log line is serialized as a JSON object with the following
-      set of keys and their associated values.
+      Each log line is serialized as a JSON object with the set of keys and
+      their associated values shown in <xref
+      linkend="runtime-config-logging-jsonlog-keys-values"/>.
      </para>
 
-     <table>
+     <table id="runtime-config-logging-jsonlog-keys-values">
       <title>Keys and values of JSON log entries</title>
       <tgroup cols="3">
        <thead>

doc/src/sgml/logical-replication.sgml

@@ -399,7 +399,12 @@
     So the <command>UPDATE</command> is transformed into an <command>INSERT</command>.
    </para>
 
-   <table>
+   <para>
+    <xref linkend="logical-replication-row-filter-transformations-summary"/>
+    summarizes the applied transformations.
+   </para>
+
+   <table id="logical-replication-row-filter-transformations-summary">
     <title><command>UPDATE</command> Transformation Summary</title>
     <tgroup cols="3">
     <thead>