Rename OOBE overview Learn link label to “Documentation” (#48155)

## Summary of the Pull Request

Renames the OOBE welcome/overview hyperlink label from **“Documentation
on Microsoft Learn”** to **“Documentation”** for brevity and
consistency.
Scope is limited to the localized string resource used by the OOBE
overview page.

## PR Checklist

- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [x] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

## Detailed Description of the Pull Request / Additional comments

- **Resource update (OOBE Overview)**
- Updated `Oobe_Overview_DescriptionLinkText.Text` in
`src/settings-ui/Settings.UI/Strings/en-us/Resources.resw`.

```xml
<data name="Oobe_Overview_DescriptionLinkText.Text" xml:space="preserve">
  <value>Documentation</value>
</data>
```

## Validation Steps Performed

- Confirmed the OOBE overview string key now resolves to
**“Documentation”**.

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>