Split bcscale() signature

As of PHP 7.3.0, bcscale() may also be used as getter, which is not
properly reflected by making the $scale parameter optional.  Therefore,
we split the function signature.

Inspired by a patch provided by Tim van Dijen.

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@346739 c90b9560-bf6c-de11-be94-00142212c4b1

reference/bc/functions/bcscale.xml

@@ -3,20 +3,25 @@
 <refentry xml:id="function.bcscale" xmlns="http://docbook.org/ns/docbook">
  <refnamediv>
   <refname>bcscale</refname>
-  <refpurpose>Set default scale parameter for all bc math functions</refpurpose>
+  <refpurpose>Set or get default scale parameter for all bc math functions</refpurpose>
  </refnamediv>
  
  <refsect1 role="description">
   &reftitle.description;
   <methodsynopsis>
    <type>int</type><methodname>bcscale</methodname>
-   <methodparam choice="opt"><type>int</type><parameter>scale</parameter></methodparam>
+   <methodparam><type>int</type><parameter>scale</parameter></methodparam>
   </methodsynopsis>
   <para>
    Sets the default scale parameter for all subsequent calls to bc math functions that
    do not explicitly specify a scale parameter.
-   If <parameter>scale</parameter> is omitted, the function gets the current
-   scale factor.
+  </para>
+  <methodsynopsis>
+   <type>int</type><methodname>bcscale</methodname>
+   <void/>
+  </methodsynopsis>
+  <para>
+   Gets the current scale factor.
   </para>
  </refsect1>
 
@@ -39,7 +44,7 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <para>
-   Returns the old scale.
+   Returns the old scale when used as setter. Otherwise the current scale is returned.
   </para>
  </refsect1>