Note deprecated get_defined_functions argument. (#4893)

* Note deprecated get_defined_functions argument.

* Add formal deprecation warning.

* Remove redundant text

Co-authored-by: Tim Düsterhus <[email protected]>

---------

Co-authored-by: Tim Düsterhus <[email protected]>

Author: Crell

reference/funchand/functions/get-defined-functions.xml

@@ -24,8 +24,10 @@
     <term><parameter>exclude_disabled</parameter></term>
     <listitem>
      <para>
-      Whether disabled functions should be excluded from the return value.
+      Whether disabled functions should be excluded from the return value. This parameter has no effect
+      since PHP 8.0.0.
      </para>
+     &warn.deprecated.feature-8-5-0;
     </listitem>
    </varlistentry>
   </variablelist>
@@ -53,11 +55,20 @@
      </row>
     </thead>
     <tbody>
+     <row>
+      <entry>8.5.0</entry>
+      <entry>
+       The <parameter>exclude_disabled</parameter> parameter has been deprecated,
+       as it no longer has any effect.
+      </entry>
+     </row>
      <row>
       <entry>8.0.0</entry>
       <entry>
        The default value of the <parameter>exclude_disabled</parameter> parameter
-       has been changed from &false; to &true;.
+       has been changed from &false; to &true;.  However, it will not have
+       any effect as disabled functions are removed from the function table at
+       compile time.
       </entry>
      </row>
      <row>