Suggested clarification on Target subletting logic and on repeatability

[Joe Darcy]

Hi Alex,

Two suggested clarifications to the 2012-08-17 version of the 
specification [1]:

* Repeatability per target.  It would be helpful if section 9.7 included 
at least an informative note that an annotation type can be viewed as 
being repeatable on a per-target basis depending on the declaration of 
the target list of the container annotation.  There is a similar note on 
this point in 9.6 but I think it bears mention in 9.7 too.

* For the purposes of checking Target subsetting in 9.6, the set 
{ElementType.ANNOTATION_TYPE} is a subset of {ElementType.TYPE} since 
annotation types are a subset of general types.

Cheers,

-Joe

[1] http://cr.openjdk.java.net/~abuckley/8misc.pdf