minor #20968 [DI] Fix DefinitionDecorator existency for composer authoritative+IDEs (nicolas-grekas)
minor #20968 [DI] Fix DefinitionDecorator existency for composer authoritative+IDEs (nicolas-grekas)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DI] Fix DefinitionDecorator existency for composer authoritative+IDEs

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

So that the class is defined for naive parser (e.g. IDEs & composer class map generator).
Fixes autoloading in authoritative mode.

Commits
-------

9c3f755 [DI] Fix DefinitionDecorator existency for composer authoritative+IDEs

symfony/DependencyInjection,symfony/dependency-injection