Remove caveat leftover from previous approach

When we did not have `itemSchema`, we needed more guidance
about improper use of `schema`, but we don't really need it now.

Author: handrews

src/oas.md

@@ -1674,9 +1674,8 @@ For this use case, `maxLength` MAY be implemented outside of regular JSON Schema
 The `itemSchema` field is provided to support streaming use cases for sequential media types.
 Unlike `schema`, which is applied to the complete content (treated as an array as described in the [sequential media types](#sequential-media-types) section), `itemSchema` MUST be applied to each item in the stream independently, which supports processing each item as it is read from the stream.
 
-Both `schema` and `itemSchema` MAY be used in the same Media Type Object, although doing so is unlikely to have significant advantages over using the `items` keyword within the `schema` field.
-OpenAPI Description authors are responsible for avoiding the use of the `schema` in any situation where tooling may not be able to discern when the content is complete.
-For example, if partial content is read from a stream and then passed with the `schema` value to a schema evaluator that is unaware of the stream context, the results will not be meaningful as there may be additional items in the stream that are necessary to or prohibitive of successful validation.
+Both `schema` and `itemSchema` MAY be used in the same Media Type Object.
+However, doing so is unlikely to have significant advantages over using the `items` keyword within the `schema` field.
 
 ##### Special Considerations for `text/event-stream` Content