u('Principal SIS ID')->snake() return principal_sisid, not principal_sis_id

### Symfony version(s) affected

7.1

### Description

`u('Principal SIS ID')->snake()->toString()` return `principal_sisid`, intuitively it feels like it should return `principal_sis_id`.

### How to reproduce

```php
u('Principal SIS ID')->snake()->toString() 
```

