Update deploy-staging-slots.md

[azarboon]

The difference between swapping and backup is one of the points questioned in Azure certification exams. I've added the following for further clarity:

"Swapping is faster than backup because you firstly you need to configure backup settings of the app then you can restore to previous state. Also, App Service stops the target app or target slot while restoring a backup."

[prmerger-automator[bot]]

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

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[Court72]

@cephalin

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

[Court72]

@cephalin

Can you review this old PR and determine whether it needs to be closed or merged?

[v-ccolin]

I sent an email to the content owner today.

@MicrosoftDocs/public-repo-pr-review-team

[cephalin]

Deployment slots and backups are completely different features for different purposes and comparing them doesn't make sense. #please-close.