Move pg_stat_progress_vacuum to the table of Dynamic Statistics Views in doc.

Previously the description about pg_stat_progress_vacuum was in the table
of "Collected Statistics Views" in the doc. But since it repors dynamic
information, i.e., the current progress of VACUUM, its description should be
in the table of "Dynamic Statistics Views".

Back-patch to 9.6 where pg_stat_progress_vacuum was added.

Author: Amit Langote
Discussion: http://postgr.es/m/7ab51b59-8d4d-6193-c60a-b75f222efb12@lab.ntt.co.jp

doc/src/sgml/monitoring.sgml

@@ -324,6 +324,14 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
       </entry>
      </row>
 
+     <row>
+      <entry><structname>pg_stat_progress_vacuum</><indexterm><primary>pg_stat_progress_vacuum</primary></indexterm></entry>
+      <entry>One row for each backend (including autovacuum worker processes) running
+       <command>VACUUM</>, showing current progress.
+       See <xref linkend='vacuum-progress-reporting'>.
+      </entry>
+     </row>
+
     </tbody>
    </tgroup>
   </table>
@@ -515,12 +523,6 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
       yet included in <structname>pg_stat_user_functions</>).</entry>
      </row>
 
-     <row>
-      <entry><structname>pg_stat_progress_vacuum</><indexterm><primary>pg_stat_progress_vacuum</primary></indexterm></entry>
-      <entry>One row for each backend (including autovacuum worker processes) running
-      <command>VACUUM</>, showing current progress.
-      See <xref linkend='vacuum-progress-reporting'>.</entry>
-     </row>
     </tbody>
    </tgroup>
   </table>