service/dynamodb: Fix package doc typo
Fixes `provides has` -> `provides` typo in the package's doc for the (un)marshaling helpers.
@@ -3,7 +3,7 @@ AttributeValue Marshaling and Unmarshaling Helpers
Utility helpers to marshal and unmarshal AttributeValue to and
from Go types can be found in the dynamodbattribute sub package. This package
-provides has specialized functions for the common ways of working with
+provides specialized functions for the common ways of working with
AttributeValues. Such as map[string]*AttributeValue, []*AttributeValue, and
directly with *AttributeValue. This is helpful for marshaling Go types for API
operations such as PutItem, and unmarshaling Query and Scan APIs' responses.
