fix 'existing value' to 'new value'

[jlecordier]

No description provided.

[PRMerger15]

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

[WilliamDAssafMSFT]

Thanks @jlecordier for submitting this PR! Apologies for the delay in reviewing, we've reviewed, your commit will be merged, and this article update is in flight. After the updated article is published, GitHub will list you as an article contributor.
#sign-off

[PRMerger7]

@WilliamDAssafMSFT: I'm sorry - only the author of this article, @jovanpop-msft, can sign off on your changes. But we do have an exception process - if you are on the Microsoft content or product team for this product area, you can ask the PR review team to review and merge it by sending mail to the techdocprs alias.