Add PowerShell syntax highlighting

[eric-schneider]

Adds PowerShell syntax highlighting, removes redundant var method for implementing INI syntax highlighting.

[github-actions]

UI bundle preview build successful! ✅
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[plpesvc-ds]

Build successful! ✅
Deploying draft.
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[plpesvc-ds]

The draft build for this pull request has been cleaned up due to being stale.

Draft builds 2 weeks old or older were automatically removed.

You can rebuild the draft at any time by pushing a new commit to this pull request:

git checkout powershell-highlighting
git commit --allow-empty -m 'rebuild draft'
git push origin powershell-highlighting