Minor document typo

Hi,

doc/src/sgml/monitoring.sgml seems to have a minor typo:

In pg_stat_database_conflicts section (around line 3621) we have:

      <para>
       Number of uses of logical slots in this database that have been
       canceled due to old snapshots or too low a <xref linkend="guc-wal-level"/>
       on the primary
      </para></entry>

I think "too low a" should be "too low" ('a' is not
necessary). Attached is the patch.

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 053da8d6e4..56e79b1304 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -3618,7 +3618,7 @@ description | Waiting for a newly initialized WAL file to reach durable storage
       </para>
       <para>
        Number of uses of logical slots in this database that have been
-       canceled due to old snapshots or too low a <xref linkend="guc-wal-level"/>
+       canceled due to old snapshots or too low <xref linkend="guc-wal-level"/>
        on the primary
       </para></entry>
      </row>