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).

Start with the docs\xml\Android.Locations files and the ns-Android.Locations.xml files identified by the provided rg command. Review the existing Android.Locations documentation and related documentation PRs before replacing the remaining "To be added" placeholders. Done means the scan reports no remaining placeholders in this namespace.

Written by the indexing model from the issue text.