Cannot scroll to heading with label "Contents"

[seshrs]

Describe the bug
When a page contains a heading titled "Contents", AnchorJS gives it HTML id="contents". However, this conflicts with the Sidebar's "Contents" header with the same ID — as a result, using the internal link https://<page-url>#contents does not cause the page to scroll to the correct place. (In fact, this can be seen on the demo page for Primer Spec itself.)

To Reproduce
Steps to reproduce the behavior:

1. Go to the Primer Spec demo page: https://eecs485staff.github.io/primer-spec/
2. Click on 'Contents' in the Sidebar.

Page does not scroll.

Expected behavior
Page should scroll to the "Contents" section in the main content.