#389 Constrain `Annotation` type parameter to ceylon.language.Annotation

for method  Package.annotatedMembers()
#389 Constrain `Annotation` type parameter to ceylon.language.Annotation

for methods:
 - ClassOrInterfaceDeclaration.annotatedMemberDeclarations()
 - ClassOrInterfaceDeclaration.annotatedDeclaredMemberDeclarations()
Formatting
Merge pull request #420 from loicrouchon/contrain-annotation-type-in-metamodel

Fix #389: Contrain annotation type in metamodel