Avoid homonym "target path"

The CSDL specs use "target path" with two rather different meanings:

1. In navigation property binding target and in action import / function import entity set it identifies the entity set of related or returned entities.
2. In annotation target it identifies the annotated model element.

The syntax of the first kind of target path is defined in section 15.4 Target Path.

The syntax of the second kind of target path is defined in section 14.2.2 Target, and this section is the only place where "target path" is used for the second meaning, and only once.