XPath query does not return root.

[grokys]

Describe the bug

XPath queries such as AutomationElement.FindFirstByXPath do not consider the root element for queries so queries such as //Window return no elements.

Code snippets

[Test]
public void WindowFindFirst()
{
    RestartApplication();

    var window = Application.GetMainWindow(Automation);
    var result = window.FindFirstByXPath($"//Window");
    Assert.That(result, Is.Not.Null);
}

Additional context

An XPath query should consider the root of the query in the results. For example, go to http://xpather.com/ and enter //app: the root element is returned. This behavior is correct in e.g. WinAppDriver.

Alternatively, run the following code:

var doc = XDocument.Parse("<root><child>text</child></root>");
var node = doc.Root!.XPathSelectElement("//root"); // root is found