Document that `AnnotationSupport.isAnnotated()` does not find repeatable annotations

[sbrannen]

Overview

The regression reported in #4054 was likely caused by confusion about the semantics of AnnotationSupport.isAnnotated().

Although one might assume that isAnnotated() would return true if the given annotation type is present as a repeatable annotation, it does not actually find repeatable annotations.

Instead, one must use one of the findRepeatableAnnotations() variants and check if the returned list is not empty to reliably determine if an element is annotated with a repeatable annotation.

Related Issues

• Repeated @ExtendWith meta-annotations on fields no longer supported in 5.11.x #4054

Deliverables

• Update the Javadoc for both AnnotationSupport.isAnnotated() variants to reflect this.
• Update the User Guide documentation for AnnotationSupport to reflect this, if applicable.
• Update the Javadoc for AnnotatedElementContext.isAnnotated() to reflect this.

[YongGoose]

@marcphilipp

Although I’ve been working on many tasks in the JUnit 5 project, this issue seems to be more about documentation.
Therefore, I believe I can handle it simultaneously.

Through this issue, I hope to further improve my documentation skills 😅

ps. If my workload makes someone else more suitable for this task, I’d be glad to let them take it on❕

[marcphilipp]

Sure, go for it! 👍