Clarify wording on encoding field (3.1.1)

The previous wording could be read to only restrict what sort
of request bodies could use an Encoding Object, while allowing that
it could be used with other entities that use a Media Type Object.

This emphasizes that it is only relevant to Request Body Objects,
and within that, only for specific media types.

Author: handrews

versions/3.1.1.md

@@ -1388,7 +1388,7 @@ Field Name | Type | Description
 <a name="mediaTypeSchema"></a>schema | [Schema Object](#schemaObject) | The schema defining the content of the request, response, or parameter.
 <a name="mediaTypeExample"></a>example | Any | Example of the media type.  The example object SHOULD be in the correct format as specified by the media type.  The `example` field is mutually exclusive of the `examples` field.  Furthermore, if referencing a `schema` which contains an example, the `example` value SHALL _override_ the example provided by the schema.
 <a name="mediaTypeExamples"></a>examples | Map[ `string`, [Example Object](#exampleObject) \| [Reference Object](#referenceObject)] | Examples of the media type.  Each example object SHOULD  match the media type and specified schema if present.  The `examples` field is mutually exclusive of the `example` field.  Furthermore, if referencing a `schema` which contains an example, the `examples` value SHALL _override_ the example provided by the schema.
-<a name="mediaTypeEncoding"></a>encoding | Map[`string`, [Encoding Object](#encodingObject)] | A map between a property name and its encoding information. The key, being the property name, MUST exist in the schema as a property. The encoding object SHALL only apply to `requestBody` objects when the media type is `multipart` or `application/x-www-form-urlencoded`.
+<a name="mediaTypeEncoding"></a>encoding | Map[`string`, [Encoding Object](#encodingObject)] | A map between a property name and its encoding information. The key, being the property name, MUST exist in the schema as a property. The encoding attribute SHALL only apply to [Request Body Objects](#requestBodyObject), and only when the media type is `multipart` or `application/x-www-form-urlencoded`.
 
 This object MAY be extended with [Specification Extensions](#specificationExtensions).
 
@@ -1601,7 +1601,7 @@ requestBody:
               $ref: '#/components/schemas/Address'
 ```
 
-An `encoding` attribute is introduced to give you control over the serialization of parts of `multipart` request bodies.  This attribute is _only_ applicable to `multipart` and `application/x-www-form-urlencoded` request bodies.
+An `encoding` attribute is introduced to give you control over the serialization of parts of `multipart` request bodies.  This attribute is _only_ applicable to request bodies, and _only_ for `multipart` and `application/x-www-form-urlencoded` media types.
 
 #### <a name="encodingObject"></a>Encoding Object