Add typehints to \Drupal\Core\File\FileSystemInterface

I will take a look on it.

Hi please revise.

Seems to have CC failure if that can be resolved please.

Hi I fixed it please revise

Needs work for MR review comments.

Hi the delete function and deleteRecursive function are returning a boolean value instead a void type mentioned in the bitbucket
and then I changed to bool type. Please revise.

There are build errors.

Hi I fixed all of them please can you tell me what is wrong?

(Tests are passing)

Migrating Pittsburgh 2023 to Pittsburgh2023 tag for cleanup

Hi I just rebased, @kim.pepper please can you tell me the next steps?

Hi Please revise.

Open threads appear to have been addressed.

The proposed changes to date look good.

Can we add detail about the backwards compatibility story to the summary. Do we need a change notice?

We may as well add rich return type detail for \Drupal\Core\File\FileSystemInterface::scanDirectory and doScanDirectory since this issue is about improving typehints. Either modify @return array, or if Drupal coding standards do not pass then use @phpstan-return with something like @phpstan-return array<string, object{uri: string, filename: string, name: string}>. I believe Drupal CS may still have issues with spaces; remove spaces, it will work just as well.

For #18