Fix markdown highlights

[johlju]

Pull Request (PR) description

• SqlServerDsc
  • Update markdown highlights with newly supported keywords.

This Pull Request (PR) fixes the following issues

None.

Task list

• Added an entry to the change log under the Unreleased section of the
  file CHANGELOG.md. Entry should say what was changed and how that
  affects users (if applicable), and reference the issue being resolved
  (if applicable).
• Resource documentation updated in the resource's README.md.
• Resource parameter descriptions updated in schema.mof.
• Comment-based help updated, including parameter descriptions.
• Localization strings updated.
• Examples updated.
• Unit tests updated. See DSC Community Testing Guidelines.
• Integration tests updated (where possible). See DSC Community Testing Guidelines.
• Code changes adheres to DSC Community Style Guidelines.

---

This change is 

[codecov]

Codecov Report

Merging #1978 (4f3eda4) into main (85f8523) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@         Coverage Diff          @@
##           main   #1978   +/-   ##
====================================
  Coverage    92%     92%           
====================================
  Files        93      93           
  Lines      7840    7840           
====================================
  Hits       7214    7214           
  Misses      626     626           

Flag	Coverage Δ
unit	92% <ø> (ø)

Files	Coverage Δ
source/Classes/020.SqlDatabasePermission.ps1	99% <ø> (ø)
source/Classes/020.SqlPermission.ps1	99% <ø> (ø)

[johlju]

Reviewed 13 of 13 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @johlju)