Add XML documentation for Android.Net.Wifi.Hotspot2.Pps

The `Android.Net.Wifi.Hotspot2.Pps` namespace contains **97** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

Example command:

```powershell
rg -n -i --glob 'Android.Net.Wifi.Hotspot2.Pps/**' --glob 'ns-Android.Net.Wifi.Hotspot2.Pps.xml' 'to be added' docs\xml
```

## Update log

- 2026-09-10: Refreshed the placeholder scan from **87** to **97** (increased by **10**). Related documentation PRs: [#644](https://github.com/dotnet/android-api-docs/pull/644).

Run the provided ripgrep command from the repository root to enumerate the 97 placeholders under docs\xml in the Android.Net.Wifi.Hotspot2.Pps paths and namespace XML file. Read those XML entries and replace each "To be added" description with accurate documentation; done means the scan returns no remaining placeholders in this namespace.

Written by the indexing model from the issue text.