Add missing MAUI API docs

[Eagle3386]

Description

Plenty of MAUI's API documentation is missing within VS IntelliSense, e. g. after typing

MauiApp.CreateBuilder().

none of the MauiAppBuilder extensions, e. g. UseMauiApp<T>() or even ConfigureFonts(), provide any information besides their method signature due to missing XML docs within their source code:

maui/src/Controls/src/Xaml/Hosting/AppHostBuilderExtensions.cs

Lines 29 to 33 in 0ace122

	public static partial class AppHostBuilderExtensions
	{
	public static MauiAppBuilder UseMauiApp<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] TApp>(this MauiAppBuilder builder)
	where TApp : class, IApplication
	{

maui/src/Core/src/Hosting/Fonts/FontsMauiAppBuilderExtensions.cs

Lines 16 to 20 in 0ace122

	}
	public static MauiAppBuilder ConfigureFonts(this MauiAppBuilder builder, Action<IFontCollection>? configureDelegate)
	{
	builder.Services.TryAddSingleton<IEmbeddedFontLoader>(svc => new EmbeddedFontLoader(svc));

Steps to Reproduce

1. Create a File > New .NET MAUI App
2. Go to CreateMauiApp() inside MauiProgram.cs.
3. At the line with MauiApp.CreateBuilder(), type a . after the closing parenthesis.

Version with bug

Release Candidate 3 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS, Android, Windows, macOS, Other (Tizen, Linux, etc. not supported by Microsoft directly)

Affected platform versions

Any supported platform version up to now

Did you find any workaround?

Nope. 😢

Relevant log output

None available. 😢

[janseris]

Good point. A lot of MAUI API misses documentation. For example MAUI Graphics code as well. I had to look up the source code on GitHub to be able to find out how it works for every function I use. (IImage API) - I checked right now on GA - the docs are still not there.

Edit: I'm always on the latest MAUI

Microsoft.Maui.Storage:

[Eilon]

BTW in .NET MAUI 6 GA (that we released this week) you should see a TON more documentation for APIs. It's certainly not complete, but prior to that, there were ZERO docs visible for the main MAUI APIs.

[Eagle3386]

@Eilon Neither is the case - I had some (very few, but still) prior to GA release, yet still after its release essential docs (e. g. both methods in my OP are part of any new MAUI project) remain missing.

[Eilon]

@Eilon Neither is the case - I had some (very few, but still) prior to GA release, yet still after its release essential docs (e. g. both methods in my OP are part of any new MAUI project) remain missing.

Understood, and I agree that many API docs are still missing. My comment was that prior to GA there were essentially ZERO API docs visible in VS, and starting with GA (released this week) there are many thousands of API docs available. Unfortunately, the APIs you mentioned are still not available.

[VincentBu]

repro with vs main build (32605.41.main)

[samhouts]

Duplicate of #3960