Add XML documentation for Android.Locations

The `Android.Locations` namespace contains **591** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

Example command:

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

## Update log

- 2026-09-10: Refreshed the placeholder scan from **1,097** to **591** (reduced by **506**). Related documentation PRs: [#567](https://github.com/dotnet/android-api-docs/pull/567), [#636](https://github.com/dotnet/android-api-docs/pull/636), [#644](https://github.com/dotnet/android-api-docs/pull/644), [#670](https://github.com/dotnet/android-api-docs/pull/670).