[Validation] Add "hasser" support
Add "versionadded" directive for 2.5
fix "versionadded" wording
feature #3418 [Validation] Add "hasser" support (bicpi)

This PR was merged into the master branch.

Discussion
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[Validation] Add "hasser" support

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes (symfony/symfony#9097)
| Applies to    | master
| Fixed tickets | -

Commits
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b9f8b8d fix "versionadded" wording
bb9004e Add "versionadded" directive for 2.5
bfe3a20 [Validation] Add "hasser" support