imap_mail_move() does actually copy and delete

Cf. <https://github.com/php/php-src/issues/7719>.

Author: cmb69

reference/imap/functions/imap-mail-copy.xml

@@ -57,7 +57,8 @@
         <listitem>
          <simpara>
           <constant>CP_MOVE</constant> - Delete the messages from
-          the current mailbox after copying
+          the current mailbox after copying. If this flag is set, the function
+          behaves identically to <function>imap_mail_move</function>.
          </simpara>
         </listitem>
        </itemizedlist>

reference/imap/functions/imap-mail-move.xml

@@ -16,7 +16,10 @@
   </methodsynopsis>
   <para>
    Moves mail messages specified by <parameter>message_nums</parameter> to the
-   specified <parameter>mailbox</parameter>. 
+   specified <parameter>mailbox</parameter>.
+   Note that the mail messages are actually <emphasis>copied</emphasis> to the
+   <parameter>mailbox</parameter>, and the original messages are flagged for deletion.
+   That implies that the messages in <parameter>mailbox</parameter> are assigned new UIDs.
   </para>
  </refsect1>
  <refsect1 role="parameters">