Accessibility-insights-web: Guidance in Headings for top-level should be best practice

[ferBonnin]

Describe the bug

This sentence, "Use exactly one top-level heading. (WCAG 1.3.1)" is still on the "Guidance for Headings" page, but that is not a WCAG violation.

To Reproduce
Go to Assessment > Headings> Guidance >Do's

Expected behavior

the "WCAG 1.3.1" in parentheses should be replaced with "best practice"

Context (please complete the following information)

Accessibility Insights for Web
Version 2.16.0 | Powered by axe-core 3.5.1

Additional context

reported by a user

[msft-github-bot]

This issue has been marked as ready for team triage; we will triage it in our weekly review and update the issue. Thank you for contributing to Accessibility Insights!

[Shobhit1]

Fixed.

[ferBonnin]

Validated in Canary 2020.4.16.19

Thanks for the fix @Shobhit1!