JDK 15 RFR of JDK-8225540: In core reflection note whether returned annotations are declaration or type annotations

[Joe Darcy]

Hello,

Please review the changes to fix

     JDK-8225540: In core reflection note whether returned annotations 
are declaration or type annotations
     http://cr.openjdk.java.net/~darcy/8225540.1/

This is a sibling fix to JDK-8225495 already done over in 
javax.lang.model. In brief, the purpose of the change is to make 
explicit whether declaration annotations (that is traditional 
annotations in the platform since JDK 5.0) or type annotations (added in 
JDK 8) are being returned by the various annotation-returning methods. 
The distinctions between the two kinds of annotations are discussed in 
the cited sections of JLS.

The root interface of types that can return annotations is 
AnnotatedElement. Some of the wording developed for JDK-8225495 is 
borrowed and repurposed as a general explanation in AnnotatedElement.  
The implementation specification of the default method for 
AnnotatedElement.isAnnotationPresetn is pull out to properly use an 
@implSpec tag. The AnnotatedType interface and its subinterfaces return 
type annotations; the other class and interfaces return declaration 
annotations.

For AnnotatedType, the three methods on AnnotatedElement that do *not* 
have default methods are overriden for the sole purpose of adding a note 
stating any return annotations are *type* annotations. The specs of the 
default methods rely on the behavior of the non-default methods so this 
implicitly implies the results of the other methods are type annotations 
too.

Since there is no common superclass of the various classes which can 
return declaration annotations, analogous notes are spread through many 
classes including

     * java.lang.Class
     * java.lang.Package
     * java.lang.Module
     * java.reflect.{AccessibleObject, Executable, Constructor, Method, 
Field, Parameter, RecordComponent}

These classes are also updated to use @Override consistently for the 
annotation-related methods; @Override couldn't initially be used on 
interface methods implemented by a class.

The Executable.getParameterAnnotations method also get a note to state 
it returns declaration annotations.

I'll update copyright and reflow paragraphs before pushing.

Thanks,

-Joe