Properties that have ToString() called on them do not escape XML

[jeremy-morren]

If a property is formatted via ToString(), XML characters are not escaped

var logger = new LoggerConfiguration()
    .WriteTo.RichTextBox(LogTextBox)
    .CreateLogger();

// Succeeds
logger.Information("URL {Url}", "http://localhost?1&2");

// XAML parse exception
logger.Information("URL {Url}", new Uri("http://localhost?1&2"));