Add XML documentation for Android.Views.InputMethods

The `Android.Views.InputMethods` namespace contains **1,004** `To be added` placeholders in source XML documentation (excluding `docs\xml\index.xml`).

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

## Update log

- 2026-09-10: Refreshed the placeholder scan from **1,622** to **1,004** (reduced by **618**). Related documentation PRs: [#360](https://github.com/dotnet/android-api-docs/pull/360), [#575](https://github.com/dotnet/android-api-docs/pull/575), [#644](https://github.com/dotnet/android-api-docs/pull/644), [#662](https://github.com/dotnet/android-api-docs/pull/662).

Start with the provided rg command and inspect the matching files under docs\xml\Android.Views.InputMethods and ns-Android.Views.InputMethods.xml. Replace the 1,004 `To be added` placeholders with XML documentation, then rerun the scan to confirm no matching placeholders remain, excluding docs\xml\index.xml.

Vom Indexierungsmodell aus dem Issue-Text verfasst.