Returns the type defined by this element.
A generic element defines a family of types, not just one.
If this is a generic element, a prototypical type is
returned. This is the element's invocation on the
type variables corresponding to its own formal type parameters.
for the generic class element
C<N extends Number>,
the parameterized type
C<N> is returned.
Types utility interface has more general methods
for obtaining the full range of types defined by an element.