Add XML documentation for Android.Service.Controls.Actions

The `Android.Service.Controls.Actions` namespace contains **94** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

Example command:

```powershell
rg -n -i --glob 'Android.Service.Controls.Actions/**' --glob 'ns-Android.Service.Controls.Actions.xml' 'to be added' docs\xml
```

Start in docs\xml using the provided rg command, checking the Android.Service.Controls.Actions namespace files and ns-Android.Service.Controls.Actions.xml for the 94 "To be added" placeholders. Read the surrounding XML documentation and relevant Android API context before filling them. Done means the namespace's source XML documentation no longer contains those placeholders, excluding docs\xml\index.xml.

索引モデルが issue の本文から書いたものです。