Update prerequisites.md

[bjompen]

This PR removes an unnecessary backtick. The PowerShell example had an accidental backtick in the command line making the single command multiline...

[prmerger-automator[bot]]

@bjompen : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[Court72]

@steved0x

Can you review the proposed changes?

Important: When the changes are ready for publication, adding a #sign-off comment is the best way to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged" @MicrosoftDocs/public-repo-pr-review-team