internal index needs more precise location information for annotations and their attributes

[martinlippert]

At the moment, the index contains precise location information for beans and injection points, but not on the more fine-grained level of annotations and their attributes. In order to implement more precise results when users search for references, we need to add more precise location information to those annotation and attribute elements in the index.

[martinlippert]

The basic infrastructure is in place and used by the "find all references" features for various annotations.