Spellchecking: Update spell-checking dictionary (#42294)

## Summary of the Pull Request

This PR updates the spell-checking dictionaries to fix outstanding
errors, and also clears up accumulated warnings.

- Cleans up duplicate or ignored entries in expect.txt:
    - `Authenticode` (favoring existing `authenticode`)
    - `DTo` (favoring existing `dto`)
    - `ekus` (favoring existing `eku`)
    - `nullrefs` (favoring existing `nullref`)
- Removes `CursorWrap` (invalid entry since camel case is treated as
separate words and is not allowed)
- Updates the pattern for `amazon.com` URLs to allow them within C#
strings
- Explicitly excludes the CmdPal sample page for images in Markdown with
Base64 encoded data from spell-checking (was previously auto-excluded)
- Suppresses spell-checking on lines with URLs containing encoded data

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## PR Checklist

- [ ] Closes: #xxx
- [ ] **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

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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

src/modules/cmdpal/ext/SamplePagesExtension/Pages/SampleListPageWithDetails.cs

@@ -63,7 +63,7 @@ internal sealed partial class SampleListPageWithDetails : ListPage
                 Details = new Details()
                 {
                     Title = "Hero Image Example",
-                    HeroImage = new IconInfo("https://m.media-amazon.com/images/M/MV5BNDBkMzVmNGQtYTM2OC00OWRjLTk5OWMtNzNkMDI4NjFjNTZmXkEyXkFqcGdeQXZ3ZXNsZXk@._V1_QL75_UX500_CR0,0,500,281_.jpg"),
+                    HeroImage = new IconInfo("https://m.media-amazon.com/images/M/MV5BNDBkMzVmNGQtYTM2OC00OWRjLTk5OWMtNzNkMDI4NjFjNTZmXkEyXkFqcGdeQXZ3ZXNsZXk@._V1_QL75_UX500_CR0,0,500,281_.jpg"), /* #no-spell-check-line */
                     Body = "It is literally an image of a hero",
                 },
             },