Fix Korean mistranslation of "Activation modifier key" in Grab And Move settings (#47352)

The Korean translation of "Activation modifier key"
(`GrabAndMove_ModifierKey.Header`) was rendered as "정품인증 보조키" ("product
authentication/genuine certification modifier key") — conflating feature
activation with Windows product licensing. The correct translation is
"활성화 보조 키".

## Change

- **`src/settings-ui/Settings.UI/Strings/en-us/Resources.resw`**:
Expanded the `<comment>` on `GrabAndMove_ModifierKey.Header` to
explicitly disambiguate "Activation" for translators:

```xml
<comment>Drop-down to choose which modifier key (Alt or Win) activates Grab And Move drag and resize.
"Activation" here means to enable/trigger the feature (활성화 in Korean),
NOT product authentication/genuine certification (정품인증 in Korean).</comment>
```

## 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
- [ ] **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

The word "Activation" is ambiguous in Korean: it can refer to Windows
product license activation (정품인증) or feature enablement (활성화). The
localization pipeline picked the wrong interpretation. Adding an
explicit in-source comment with both the correct and incorrect Korean
terms guides the translation tooling and human reviewers to use "활성화 보조
키" going forward.

## Validation Steps Performed

- Verified the updated comment appears correctly in the `.resw` file.
- No runtime behavior changes; comment-only modification to the resource
file.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: niels9001 <9866362+niels9001@users.noreply.github.com>

Author: Copilot

src/settings-ui/Settings.UI/Strings/en-us/Resources.resw

@@ -6083,7 +6083,7 @@ Text uses the current drawing color.</value>
   </data>
   <data name="GrabAndMove_ModifierKey.Header" xml:space="preserve">
     <value>Activation modifier key</value>
-    <comment>Drop-down to choose which modifier key (Alt or Win) activates Grab And Move drag and resize.</comment>
+    <comment>Drop-down to choose which modifier key (Alt or Win) activates Grab And Move drag and resize. "Activation" here means to enable/trigger the feature (활성화 in Korean), NOT product authentication/genuine certification (정품인증 in Korean).</comment>
   </data>
   <data name="GrabAndMove_ModifierKey_Alt.Content" xml:space="preserve">
     <value>Alt</value>