Revise documentation for SpEL `PropertyAccessor` and `IndexAccessor` APIs regarding ordering

[sbrannen]

Overview

This is a follow-up to #33861 to ensure that the Javadoc for TargetedAccessor, PropertyAccessor, and IndexAccessor now clearly aligns with the underlying ordering algorithm.

Related Issues

• SpEL PropertyAccessor ordering for supertype and generic matches does not adhere to contract #33861
• An action without parameters results in NoSuchMethodException starting with Spring Framework 6.2.0-M1 spring-webflow#1802