Update doc comment

It now states that either the container type or element type can be passed to the filter creation instead of forcing it to be the element type.

filter.go

@@ -24,8 +24,8 @@ func getElementType(dataType interface{}) reflect.Type {
 }
 
 // Creates a filter to operate on the given data type.
-// The data type is the type of the elements that will be filtered and not the top level container type.
-// For example, if you want to filter a []Foo then the data type to pass here is Foo.
+// The data type passed can be either be a container type (map, slice or array) or the element type.
+// For example, if you want to filter a []Foo then the data type to pass here is either []Foo or just Foo.
 // If no expression is provided the nil filter will be returned but is not an error. This is done
 // to allow for executing the nil filter which is just a no-op
 func CreateFilter(expression string, config *EvaluatorConfig, dataType interface{}) (*Filter, error) {