minor #40527 [Runtime] Dont use "parent" as type hint (Nyholm)
minor #40527 [Runtime] Dont use "parent" as type hint (Nyholm)

This PR was merged into the 5.3-dev branch.

Discussion
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[Runtime] Dont use "parent" as type hint

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | no (minor)
| New feature?  | no
| Deprecations? | no
| Tickets       |
| License       | MIT
| Doc PR        |

The type hint `parent` is weird and confusing. PHPStorm also warned be that it is not supported on PHP 7.2 and 7.3.

I replace this will `GenericRuntime` instead. It will make it easier to extend `SymfonyRuntime`.

Commits
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4f486e850a [Runtime] Dont use "parent" as type hint

curry684/symfony,derrabus/symfony,damienalexandre/symfony,nicolas-grekas/symfony,hhamon/symfony,ogizanagi/symfony,Tobion/symfony,mpdude/symfony,sgehrig/symfony,xabbuh/symfony,ogizanagi/symfony,paradajozsef/symfony,ro0NL/symfony,mpdude/symfony,damienalexandre/symfony,xabbuh/symfony,ro0NL/symfony,HeahDude/symfony,MatTheCat/symfony,hhamon/symfony,paradajozsef/symfony,phramz/symfony,paradajozsef/symfony,hhamon/symfony,ogizanagi/symfony,sgehrig/symfony,HeahDude/symfony,phramz/symfony,stof/symfony,Nyholm/symfony,phramz/symfony,curry684/symfony,hhamon/symfony,oleg-andreyev/symfony,Tobion/symfony,d-ph/symfony,Nyholm/symfony,OskarStark/symfony,derrabus/symfony,symfony/symfony,damienalexandre/symfony,OskarStark/symfony,Tobion/symfony,d-ph/symfony,Slamdunk/symfony,oleg-andreyev/symfony,ogizanagi/symfony,tucksaun/symfony,Nyholm/symfony,nicolas-grekas/symfony,derrabus/symfony,HeahDude/symfony,OskarStark/symfony,stof/symfony,curry684/symfony,curry684/symfony,damienalexandre/symfony,stof/symfony,ro0NL/symfony,MatTheCat/symfony,ro0NL/symfony,MatTheCat/symfony,mpdude/symfony,symfony/symfony,MatTheCat/symfony,xabbuh/symfony,HeahDude/symfony,Nyholm/symfony,sgehrig/symfony,Tobion/symfony,mpdude/symfony,nicolas-grekas/symfony,symfony/symfony,phramz/symfony,oleg-andreyev/symfony,oleg-andreyev/symfony,sgehrig/symfony,nicolas-grekas/symfony,tucksaun/symfony,symfony/symfony,d-ph/symfony,Slamdunk/symfony,Slamdunk/symfony,paradajozsef/symfony,derrabus/symfony,tucksaun/symfony,Slamdunk/symfony,d-ph/symfony,xabbuh/symfony,OskarStark/symfony,tucksaun/symfony,stof/symfony