More precise sprintf() format-arg based return type

[staabm]

extracted from https://github.com/phpstan/phpstan-src/pull/3168

closes https://github.com/phpstan/phpstan/issues/11248 closes https://github.com/phpstan/phpstan/issues/10493

the previous format-type based logic was too optimistic regarding types and false-positively created too precise types in some cases.

[staabm]

I think the remaining error is a bug: https://github.com/phpstan/phpstan/issues/11249

[phpstan-bot]

This pull request has been marked as ready for review.

[staabm]

sorry for all these commits to make it finally build on php 7.2 without errors.

[ondrejmirtes]

Thank you!