Char doesn't accept null value

### Type of issue

Missing information

### Description

Hello, the article says that you can "turn off" the password mode putting the value null in a MaskedTextBox.PasswordChar ( = null) property but that accept only the type char and not char?, we can get it puttin '\0' to turn off this mode, but this isnt mentioned on the article. (if iam wrong, please tell me for learning, thanks).

### Page URL

https://learn.microsoft.com/pt-br/dotnet/api/system.windows.forms.maskedtextbox.passwordchar?view=windowsdesktop-9.0

### Content source URL

https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System.Windows.Forms/MaskedTextBox.xml

### Document Version Independent Id

68efb826-6f92-3f89-cc34-e8565c8363b2

### Article author

@dotnet-bot