Added clarifications about --wal-file-path to doc/pgprobackup.xml

Author: dlepikhova

doc/pgprobackup.xml

@@ -131,6 +131,7 @@ doc/src/sgml/pgprobackup.sgml
    <arg choice="plain"><option>archive-push</option></arg>
    <arg choice="plain"><option>-B</option> <replaceable>backup_dir</replaceable></arg>
    <arg choice="plain"><option>--instance</option> <replaceable>instance_name</replaceable></arg>
+   <arg choice="plain"><option>--wal-file-path</option> <replaceable>wal_file_path</replaceable></arg>
    <arg choice="plain"><option>--wal-file-name</option> <replaceable>wal_file_name</replaceable></arg>
    <arg rep="repeat"><replaceable>option</replaceable></arg>
   </cmdsynopsis>
@@ -5367,7 +5368,9 @@ pg_probackup catchup -b <replaceable>catchup_mode</replaceable>
         Provides the path to the WAL file in
         <parameter>archive_command</parameter> and
         <parameter>restore_command</parameter>. Use the <literal>%p</literal>
-        variable as the value for this option for correct processing.
+        variable as the value for this option or skip it for setting it according to
+        value from <filename>pg_probackup.conf</filename>.
+        Or explicitly specify the path to a file outside the PGDATA.
       </para>
       </listitem>
       </varlistentry>
@@ -5380,6 +5383,8 @@ pg_probackup catchup -b <replaceable>catchup_mode</replaceable>
         <parameter>archive_command</parameter> and
         <parameter>restore_command</parameter>. Use the <literal>%f</literal>
         variable as the value for this option for correct processing.
+        Or explicitly specify the filename if given a <option>--wal-file-path<option>
+        value outside the PGDATA.
       </para>
       </listitem>
       </varlistentry>