Further `clean-repo-sidebar` #3972

Also perhaps we should drop the awkward "+ 231 releases" instead of the "Releases" title.

<img width="162" alt="Screen Shot 1" src="https://user-images.githubusercontent.com/1402241/107869914-3f6a2e00-6e59-11eb-8ad7-43472da617ae.png">

Or we could drop both, while just leaving the latest tag (and releases-tag)

Actually there's more that can be removed, including the padding/border above the "Releases" section. Check this out:

<table> <tr> <td><img width="170" alt="Screen Shot 2" src="https://user-images.githubusercontent.com/1402241/107870013-5fe6b800-6e5a-11eb-8eee-8cfda3e3f1c0.png"> <td valign=top><img width="165" alt="Screen Shot 4" src="https://user-images.githubusercontent.com/1402241/107870015-61b07b80-6e5a-11eb-8a39-2d4ce6ba6835.png"> </table>