docs: def visitAnnotation(self, ctx: ShExDocParser.AnnotationContext):
          """ annotation: '//' predicate (iri | literal) """
          # Annotations apply to the expression, NOT the shape (!)
          annot = Annotation(self.context.predicate_to_IRI(ctx.predicate()))
          if ctx.iri():
              annot.object = self.context.iri_to_iriref(ctx.iri())
          else:
              annot.object = self.context.literal_to_ObjectLiteral(ctx.literal())
          self.annotations.append(annot)