Resolved undocumented nullable behavior (#2046)

* Resolved undocumented nullable behavior

OpenAPI Schema Objects and JSON Schema have a few fundamental differences, and this clears up a bit of confusion about one of them.

* Added ted updates from oct 31st TSC

Co-Authored-By: Ted Epstein <[email protected]>

versions/3.0.3.md

@@ -2326,7 +2326,7 @@ Other than the JSON Schema subset fields, the following fields MAY be used for f
 ##### Fixed Fields
 Field Name | Type | Description
 ---|:---:|---
-<a name="schemaNullable"></a>nullable | `boolean` | Allows sending a `null` value for the defined schema. Default value is `false`.
+<a name="schemaNullable"></a>nullable | `boolean` | A `true` value adds `"null"` to the allowed type specified by the `type` keyword, only if `type` is explicitly defined within the same Schema Object. Other Schema Object constraints retain their defined behavior, and therefore may disallow the use of `null` as a value. A `false` value leaves the specified or default `type` unmodified. The default value is `false`.
 <a name="schemaDiscriminator"></a>discriminator | [Discriminator Object](#discriminatorObject) | Adds support for polymorphism. The discriminator is an object name that is used to differentiate between other schemas which may satisfy the payload description. See [Composition and Inheritance](#schemaComposition) for more details.
 <a name="schemaReadOnly"></a>readOnly | `boolean` | Relevant only for Schema `"properties"` definitions. Declares the property as "read only". This means that it MAY be sent as part of a response but SHOULD NOT be sent as part of the request. If the property is marked as `readOnly` being `true` and is in the `required` list, the `required` will take effect on the response only. A property MUST NOT be marked as both `readOnly` and `writeOnly` being `true`. Default value is `false`.
 <a name="schemaWriteOnly"></a>writeOnly | `boolean` | Relevant only for Schema `"properties"` definitions. Declares the property as "write only". Therefore, it MAY be sent as part of a request but SHOULD NOT be sent as part of the response. If the property is marked as `writeOnly` being `true` and is in the `required` list, the `required` will take effect on the request only. A property MUST NOT be marked as both `readOnly` and `writeOnly` being `true`. Default value is `false`.