Fixed misleading remarks about CreditCardAttribute (#3257)

CreditCardAttribute does not use regular expressions for validation.

Author: SonnyRR

xml/System.ComponentModel.DataAnnotations/CreditCardAttribute.xml

@@ -35,7 +35,7 @@
       <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- The value is validated using a regular expression. The class does not validate that the credit card number is valid for purchases, only that it is well formed.  
+ The value is validated using a string processing algorithm. The class does not validate that the credit card number is valid for purchases, only that it is well formed.  
   
  ]]></format>
     </remarks>
@@ -101,7 +101,7 @@
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- The value is validated using a regular expression. The class does not validate that the credit card number is valid for purchases, only that it is well formed.  
+ The value is validated using a string processing algorithm. The class does not validate that the credit card number is valid for purchases, only that it is well formed.  
   
  ]]></format>
         </remarks>