minor symfony#46845 [DoctrineBridge] [ci] Sync return-type declarations (nicolas-grekas)

This PR was merged into the 6.1 branch.

Discussion
----------

[DoctrineBridge] [ci] Sync return-type declarations

| Q             | A
| ------------- | ---
| Branch?       | 6.1
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Commits
-------

437572f [ci] Sync return-type declarations

Author: nicolas-grekas