Add XML documentation for Android.Database.Sqlite

The `Android.Database.Sqlite` namespace contains **237** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

Example command:

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

## Update log

- 2026-09-10: Refreshed the placeholder scan from **231** to **237** (increased by **6**). Related documentation PRs: [#644](https://github.com/dotnet/android-api-docs/pull/644).

Run the provided rg command to enumerate the 237 placeholders under docs\xml for Android.Database.Sqlite, including ns-Android.Database.Sqlite.xml. Review each matching entry and replace the placeholder with accurate API documentation. Done means the namespace scan no longer reports these 'To be added' entries.

由索引模型根据 Issue 内容生成。