ext/ldap: Fix ldap_count_entries() return value documentation (#5218)

* ldap_count_entries(): document -1 return value on error

Author: lacatoire

reference/ldap/functions/ldap-count-entries.xml

@@ -45,9 +45,9 @@
 
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
-  <para>
-   Returns number of entries in the result,&return.falseforfailure;.
-  </para>
+  <simpara>
+   Returns the number of entries in the result, or <literal>-1</literal> on error.
+  </simpara>
  </refsect1>
 
  <refsect1 role="changelog">