Update authenticating_managed_identity.html.md

[tbalthazar]

All Submissions:

• [x] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.
• [ ] My code follows the code style of this project.
• [ ] I ran lint checks locally prior to submission.
• [ ] Have you checked to ensure there aren't other open PRs for the same update/change?

What about the current behavior has changed?

This is a minor documentation update. The closing double quote was missing, causing https://registry.terraform.io/providers/microsoft/azuredevops/latest/docs/guides/authenticating_managed_identity to not render properly, as shown in this screenshot:

Issue Number: N/A

Does this introduce a change to go.mod, go.sum or vendor/?

• [ ] Yes
• [x] No

Does this introduce a breaking change?

• [ ] Yes
• [x] No

Any relevant logs, error output, etc?

(If it’s long, please paste to https://ghostbin.com/ and insert the link here.)

Other information