Support "Application" Intellisense/Autocomplete

[vindicatorr]

I was just starting out with Avalonia and while there is intellisense, it just seems to be for controls, and nothing relating to Application.

Take the default template (App.axaml) for example:

<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="app.App">
    <Application.Styles>
        <FluentTheme Mode="Light" />
    </Application.Styles>
</Application>

If I CTRL+SPACE in there (or even in the MainWindow.axaml), I get nothing but strings found in the list (eg. "blend").
If I type '<', then CTRL+SPACE, I get a full list for Avalonia controls, from AccessText to WrapPanel.
But there's nothing relating to "Application".

Two things that I think "could" relate to adding this feature "may" be found in:
~/.nuget/packages/avalonia/0.10.0/lib/netcoreapp2.0/Avalonia.Styling.xml
~/.nuget/packages/avalonia/0.10.0/lib/netcoreapp2.0/Avalonia.Themes.Fluent.xml

I don't know how your "test" xs for Avalonia is generated, but I saw "Avalonia.Controls.xml" in the nuget directory as well, making me think it was selectively picked, making me also think those others could be added as well.

While I'm here, looking at https://avaloniaui.net/docs/advanced-tutorial/create-a-modern-window where it talks of "TransparencyLevelHint" (which is part of intellisense), I see "AcrylicBlur" doesn't come up as an intellisense option (nothing does for quoted stuff in general).
That is something found in ~/.nuget/packages/avalonia/0.10.0/lib/netstandard2.0/Avalonia.Controls.xml.