Merge pull request #3751 from handrews/disc-strings-311

Non-string discriminator values (3.1.1 port of #3728)

Author: lornajane

versions/3.1.1.md

@@ -2763,7 +2763,7 @@ Field Name | Type | Description
 
 This object MAY be extended with [Specification Extensions](#specificationExtensions).
 
-The discriminator object is legal only when using one of the composite keywords `oneOf`, `anyOf`, `allOf`.
+The discriminator object is legal only when using one of the composite keywords `oneOf`, `anyOf`, `allOf`.  Note that because the discriminating property's value is used as a component name and/or as the key in the `mapping` object, the behavior of any value that is not a string is undefined.
 
 In OAS 3.x, a response payload MAY be described to be exactly one of any number of types: