doc: Fix a few typos and awkward links

doc/src/sgml/backup.sgml

@@ -878,7 +878,7 @@ SELECT pg_start_backup('label', false, false);
      <application>pg_dump</application> or
      <application>pg_dumpall</application>).  It is neither
      necessary nor desirable to stop normal operation of the database
-     while you do this. See section
+     while you do this. See
      <xref linkend="backup-lowlevel-base-backup-data"> for things to
      consider during this backup.
     </para>
@@ -988,7 +988,7 @@ SELECT pg_start_backup('label', true);
      <application>pg_dump</application> or
      <application>pg_dumpall</application>).  It is neither
      necessary nor desirable to stop normal operation of the database
-     while you do this. See section
+     while you do this. See
      <xref linkend="backup-lowlevel-base-backup-data"> for things to
      consider during this backup.
     </para>

doc/src/sgml/config.sgml

@@ -532,10 +532,10 @@ include_dir 'conf.d'
       </term>
       <listitem>
        <para>
-         Specifies the configuration file for
-         <xref linkend="auth-username-maps"> user name mapping
+         Specifies the configuration file for user name mapping
          (customarily called <filename>pg_ident.conf</>).
          This parameter can only be set at server start.
+         See also <xref linkend="auth-username-maps">.
        </para>
       </listitem>
      </varlistentry>

doc/src/sgml/ecpg.sgml

@@ -1189,7 +1189,7 @@ EXEC SQL END DECLARE SECTION;
       There are two use cases for arrays as host variables.  The first
       is a way to store some text string in <type>char[]</type>
       or <type>VARCHAR[]</type>, as
-      explained <xref linkend="ecpg-char">.  The second use case is to
+      explained in <xref linkend="ecpg-char">.  The second use case is to
       retrieve multiple rows from a query result without using a
       cursor.  Without an array, to process a query result consisting
       of multiple rows, it is required to use a cursor and

doc/src/sgml/high-availability.sgml

@@ -207,7 +207,7 @@ protocol to make nodes agree on a serializable transactional order.
      middleware.  Care must also be taken that all
      transactions either commit or abort on all servers, perhaps
      using two-phase commit (<xref linkend="sql-prepare-transaction">
-     and <xref linkend="sql-commit-prepared">.
+     and <xref linkend="sql-commit-prepared">).
      <productname>Pgpool-II</> and <productname>Continuent Tungsten</>
      are examples of this type of replication.
     </para>

doc/src/sgml/protocol.sgml

@@ -2296,8 +2296,8 @@ The commands accepted in walsender mode are:
 
   <para>
    The individual protocol messages are discussed in the following
-   subsections. Individual messages are describer in
-   <xref linkend="protocol-logicalrep-message-formats"> section.
+   subsections. Individual messages are described in
+   <xref linkend="protocol-logicalrep-message-formats">.
   </para>
 
   <para>