OpenAPI 3.x.y - Parameter Object, style field allowed values

[char0n]

We currently only have linting rule to check for the value type. Better rule will be to have explicit allowed values that this field can be assigned.

Allowed values: form, simple

OpenAPI spec excerpt that defines validation rules depending on context:

Describes how the parameter value will be serialized depending on the type of the parameter value. Default values (based on value of in): for query - form; for path - simple; for header - simple; for cookie - form.

Related #4645