Clarify relationship between Encoding Object and multipart/form-data

[Youssef1313]

In "4.15.4.5 Example: Multipart Form with Multiple Files"

https://spec.openapis.org/oas/v3.2.0.html#example-multipart-form-with-multiple-files

As seen in the Encoding Object’s contentType field documentation, the empty schema for items indicates a media type of application/octet-stream.

However, the example is dealing with Schema Object. So I don't see how/why the example relates to Encoding Object.

I can see the description making sense, but for a different reason, the fact that an empty schema matches everything, which is aligning with https://spec.openapis.org/oas/v3.2.0.html#migrating-binary-descriptions-from-oas-3-0

contentMediaType: image/png
if redundant, can be omitted, often resulting in an empty Schema Object

[karenetheridge]

The example is showing how to decode this message part. The linked section explains that when encoding/<property-name>/contentType is missing, we look at what the schema's type keyword says to determine how the part should be encoded. When type is entirely lacking, it is application/octet-stream.