Fix docs.

Author: beauby

docs/general/configuration_options.md

@@ -9,10 +9,10 @@ The following configuration options can be set on `ActiveModel::Serializer.confi
 ## JSON API
 
 - `jsonapi_resource_type`: Whether the `type` attributes of resources should be singular or plural. Possible values: `:singular, :plural`. Default: `:plural`.
-- `jsonapi_include_toplevel_member`: Whether to include a [top level JSON API member](http://jsonapi.org/format/#document-jsonapi-object)
+- `jsonapi_include_toplevel_object`: Whether to include a [top level JSON API member](http://jsonapi.org/format/#document-jsonapi-object)
    in the response document.
    Default: `false`.
-- Used when `jsonapi_include_toplevel_member` is `true`:
+- Used when `jsonapi_include_toplevel_object` is `true`:
   - `jsonapi_version`: The latest version of the spec the API conforms to.
     Default: `'1.0'`.
   - `jsonapi_toplevel_meta`: Optional metadata. Not included if empty.