added @Target annotations
minor #10767 added @Target annotations (fabpot)

This PR was merged into the 2.3 branch.

Discussion
----------

added @Target annotations

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #1930
| License       | MIT
| Doc PR        | n/a

Commits
-------

542d6fa added @Target annotations
Merge branch '2.3' into 2.4

* 2.3:
  added @Target annotations
[Validator] fixed @Target config
[Validator] added missing @Target