Merge pull request #3726 from handrews/format-vocab

Be more clear about `format` support (3.1.1)

Author: lornajane

versions/3.1.1.md

@@ -156,7 +156,8 @@ Data types in the OAS are based on the types supported by the [JSON Schema Speci
 Note that `integer` as a type is also supported and is defined as a JSON number without a fraction or exponent part. 
 Models are defined using the [Schema Object](#schemaObject), which is a superset of JSON Schema Specification Draft 2020-12.
 
-<a name="dataTypeFormat"></a>As defined by the [JSON Schema Validation vocabulary](https://tools.ietf.org/html/draft-bhutton-json-schema-validation-00#section-7.3), data types can have an optional modifier property: `format`.
+<a name="dataTypeFormat"></a>As defined by the [JSON Schema Validation specification](https://tools.ietf.org/html/draft-bhutton-json-schema-validation-00#section-7.3), data types can have an optional modifier property: `format`.  As described in that specification, `format` is treated as a non-validating annotation by default; the ability to validate `format` varies across implementations.
+
 OAS defines additional formats to provide fine detail for primitive data types.
 
 The formats defined by the OAS are: