Docs: improve examples about not repeating table name in UPDATE ... SET.

Alexander Law

doc/src/sgml/ref/insert.sgml

@@ -194,8 +194,8 @@ INSERT INTO <replaceable class="PARAMETER">table_name</replaceable> [ AS <replac
         column leaves the other fields null.)  When referencing a
         column with <literal>ON CONFLICT DO UPDATE</>, do not include
         the table's name in the specification of a target column.  For
-        example, <literal>INSERT ... ON CONFLICT DO UPDATE tab SET
+        example, <literal>INSERT INTO table_name ... ON CONFLICT DO UPDATE
-        table_name.col = 1</> is invalid (this follows the general
+        SET table_name.col = 1</> is invalid (this follows the general
         behavior for <command>UPDATE</>).
        </para>
       </listitem>

doc/src/sgml/ref/update.sgml

@@ -123,7 +123,7 @@ UPDATE [ ONLY ] <replaceable class="PARAMETER">table_name</replaceable> [ * ] [
       The column name can be qualified with a subfield name or array
       subscript, if needed.  Do not include the table's name in the
       specification of a target column &mdash; for example,
-      <literal>UPDATE tab SET tab.col = 1</> is invalid.
+      <literal>UPDATE table_name SET table_name.col = 1</> is invalid.
      </para>
     </listitem>
    </varlistentry>