This MR will also fix a bug I just found: https://gitlab.winehq.org/wine/wine/-/blob/5fa25d00d7edca295e38030006b14f405...
`ARRAY_SIZE` should be used instead, as [`RegEnumKeyExW()`](https://docs.microsoft.com/en-us/windows/win32/api/winreg/nf-winreg-regenumk...) takes the number of characters.