docs: fix incorrect default value and sample code for reduce_multiples()

Author: kenjis

user_guide_src/source/helpers/text_helper.rst

@@ -127,7 +127,7 @@ The following functions are available:
         and handle string inputs. This however makes it just an
         alias for ``stripslashes()``.
 
-.. php:function:: reduce_multiples($str[, $character = ''[, $trim = false]])
+.. php:function:: reduce_multiples($str[, $character = ','[, $trim = false]])
 
     :param    string    $str: Text to search in
     :param    string    $character: Character to reduce

user_guide_src/source/helpers/text_helper/010.php

@@ -1,4 +1,4 @@
 <?php
 
 $string = ',Fred, Bill,, Joe, Jimmy,';
-$string = reduce_multiples($string, ', ', true); // results in "Fred, Bill, Joe, Jimmy"
+$string = reduce_multiples($string, ',', true); // results in "Fred, Bill, Joe, Jimmy"