Added PHPStan-generics to preg_replace

[tjveldhuizen]

The subject in preg_replace can be a string or an arrays of strings. The return value is the same type as the provided subject. By adding the generics PHPStan 'knows' the correct return type in a situation like this:

use function Safe\preg_replace;

$foo = 'some string 123';
$bar = preg_replace('/[0-9]/', '', $foo);
$baz = trim($bar); // PHPStan complains that trim does not accept string|string[]

[ZebulanStanphill]

Support for array as an @template type bound was only very recently added to PHPStan in phpstan/phpstan-src#673, and the current PHPStan release (0.12.99), was made a few days before that PR was merged.

So the changes in this PR will work with the next PHPStan release... but until then, this PR will have to wait.

[tjveldhuizen]

Ah, so that's the reason... should we leave the PR open, or close it for now?

[ZebulanStanphill]

@tjveldhuizen PHPStan 1.0 just came out, and it includes support for @template T of array, so once this project updates its PHPStan requirement, this PR can be rebased and should start working as intended.

[Kharhamel]

Sorry I completly missed this PR. I will update the phpstan recs this week