Fixing minor grammer issues in CardScheme constraint

Sgoettschkes · Sgoettschkes · commit cc3ce38577a3 · 2013-01-09T09:27:42.000+01:00
diff --git a/reference/constraints/CardScheme.rst b/reference/constraints/CardScheme.rst
@@ -94,7 +94,7 @@ schemes
 **type**: ``mixed`` [:ref:`default option<validation-default-option>`]
 
 This option is required and represents the name of the number scheme used to 
-validate the credit card number. It can either be a String or an Array. Valid
+validate the credit card number, it can either be a string or an array. Valid
 values are:
 
 * ``AMEX``
