[PropertyInfo] Support union types through PhpDoc

[alex-dev]

Description

Currently, symfony/property-info supports union types through ReflectionExtractor and PhpStanExtractor.
phpDocumentor/reflection also supports union type values (both as a type and in collection key/value).

If PhpDocExtractor is not deprecated, it should be updated to detect union type properly especially in collections.

[alexandre-daubois]

Isn't it already supported, as highlighted by this test?
https://github.com/symfony/symfony/blob/6.1/src/Symfony/Component/PropertyInfo/Tests/Extractor/PhpDocExtractorTest.php#L121

[alex-dev]

It doesn't seems to be supported in collections. Nor is there any test I could find.

[carsonbot]

Thank you for this suggestion.
There has not been a lot of activity here for a while. Would you still like to see this feature?

[carsonbot]

Hello? This issue is about to be closed if nobody replies.

[alex-dev]

Would still be useful.

[wouterj]

Do you have time to submit a PR to add this, @alex-dev ?

[temp]

I opened #48238 with basic support for union types. It's a bit tricky, since cases that the phpstan extractor can differ can't be differentiated via the docblock types. That's why we had to unify cases $b and $c from the DummyUnionType.
Cases $d, $e, $f and $g can not be handled by the current underlying docblock structures, and are disabled.