Remove text artifact from certain pages

[melange396]

Some pages show a spurious "-->" (which could perhaps be an HTML comment close tag) just under the menu bar at the top of the page. For instance, it can be seen in the current deployment of the epidata/covidcast dashboard and epivis, but not in the blog list or the team page.

It does not appear in https://deploy-preview-1015--cmu-delphi-main.netlify.app/covidcast/

• from Release v3.2.19 #1015

But shows up in https://deploy-preview-1022--cmu-delphi-main.netlify.app/covidcast/

• from Release v3.3.0 #1022

It might have come from the HTML comment addition in themes/delphi/layouts/_default/baseof.html : https://github.com/cmu-delphi/www-main/pull/1022/files#diff-6234b75ca15fff5ac3b2c40b86a94e7fa192e6b90dd3bc21ce348bc98a163e94R11

I thought the breadcrumb thing sounded familiar, so i looked and found a suggestion i made in this comment that might be helpful: #996 (comment)