Fix PasswordCharProperty owner

src/Avalonia.Controls/MaskedTextBox.cs

@@ -32,7 +32,7 @@ namespace Avalonia.Controls
              AvaloniaProperty.Register<MaskedTextBox, string?>(nameof(Mask), string.Empty);
 
         public static new readonly StyledProperty<char> PasswordCharProperty =
-             AvaloniaProperty.Register<TextBox, char>(nameof(PasswordChar), '\0');
+             AvaloniaProperty.Register<MaskedTextBox, char>(nameof(PasswordChar), '\0');
 
         public static readonly StyledProperty<char> PromptCharProperty =
              AvaloniaProperty.Register<MaskedTextBox, char>(nameof(PromptChar), '_');