doc: Fix typos and other minor issues

Author: Alexander Lakhin <exclusion@gmail.com>

Author: petere

doc/src/sgml/event-trigger.sgml

@@ -565,6 +565,7 @@
         <entry align="center"><literal>X</literal></entry>
         <entry align="center"><literal>-</literal></entry>
         <entry align="center"><literal>-</literal></entry>
+        <entry align="center"></entry>
        </row>
        <row>
         <entry align="left"><literal>CREATE USER MAPPING</literal></entry>

doc/src/sgml/logicaldecoding.sgml

@@ -338,7 +338,7 @@ $ pg_recvlogical -d postgres --slot test --drop-slot
    <para>
     The <link linkend="view-pg-replication-slots"><structname>pg_replication_slots</structname></link>
     view and the
-    <link linkend="monitoring-stats-views-table"><structname>pg_stat_replication</structname></link>
+    <link linkend="pg-stat-replication-view"><structname>pg_stat_replication</structname></link>
     view provide information about the current state of replication slots and
     streaming replication connections respectively. These views apply to both physical and
     logical replication.

doc/src/sgml/perform.sgml

@@ -1610,7 +1610,7 @@ SELECT * FROM x, y, a, b, c WHERE something AND somethingelse;
      <listitem>
       <para>
        Increase <xref linkend="guc-max-wal-size"> and <xref
-       linkend="guc-checkpoint-timeout"> ; this reduces the frequency
+       linkend="guc-checkpoint-timeout">; this reduces the frequency
        of checkpoints, but increases the storage requirements of
        <filename>/pg_xlog</>.
       </para>