Add note about float support, but with note about setlocale() restriction

reference/en/types.txt

@@ -11,13 +11,14 @@ the supported database vendors:
 * BigInt
 * String (string with maximum length, for example 255)
 * Text (strings without maximum length)
-* Decimal (restricted floats)
+* Decimal (restricted floats, *NOTE* Only works with a setlocale() configuration that uses decimal points!)
 * Boolean
 * DateTime
 * Date (DateTime instance where only Y-m-d get persisted)
 * Time (DateTime instance where only H:i:s get persisted)
 * Array (serialized into a text field for all vendors by default)
 * Object (serialized into a text field for all vendors by default)
+* Float (*NOTE* Only works with a setlocale() configuration that uses decimal points!)
 
 Types are flyweights. This means there is only ever one instance of a type and it is not allowed to contain any state.
 Creation of type instances is abstracted through a static get method `Doctrine\DBAL\Types\Type::getType()`.