Notes about caching pages with a CSRF Form

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | no
| Applies to    | all
| Fixed tickets | #1216
well, I think the doc is missing the fact that the ``symfony/security`` component is actually distributed as 4 components now (``symfony/security`` replacing them all for BC reasons). But this is a separate topic