[FrameworkBundle] Update deprecation message

Small addition to (doc string only):
https://github.com/symfony/symfony/pull/9252
Fix nonexistent key id in twig of data collector
bug #9397 [BUG][Form] Fix nonexistent key id in twig of data collector (francoispluchino)

This PR was merged into the master branch.

Discussion
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[BUG][Form] Fix nonexistent key id in twig of data collector

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

When you create a single button form type, the id of data collector does not exist. It's caused by the PR #9394.

Commits
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19c74f3 Fix nonexistent key id in twig of data collector
minor #9389 [FrameworkBundle] Update deprecation message (asm89)

This PR was merged into the master branch.

Discussion
----------

[FrameworkBundle] Update deprecation message

Small addition to (doc string only):
https://github.com/symfony/symfony/pull/9252

Commits
-------

b057fab [FrameworkBundle] Update deprecation message