[Feature Request] Include API pages xref to xrefmap.yml when using ApiPage output format.

[filzrev]

Is your feature request related to a problem? Please describe.
When using ApiPage metadata output format.
It contains uid as metadata. But it's not exposed to xrefmap.yml

So link to ApiPage with <xref:uid> is not working.

Describe the solution you'd like
Include ApiPage's xref info to xrefmap.yml and it can resolve API page with <xref:uid>.

[filzrev]

It seems API page cross references also not works when using outputFormat: apiPage.

Example

    public interface IDummyInterface{}
    
    /// <summary>
    /// Provides a built-in <see cref="IDummy"/>.
    /// </summary>
    public class DummyClass : IDummy
    {
        public string DummyProp { get; set; }
    }

<see cref="IDummy"/> tah is expected converted to link.
But it's rendered as plain span.

<span class="xref">RoslynAnalysis.DummyInterface</span>

And uid not found warning is not reported.

When using mref output format. it works as expected.