toc:permalink somewhat broken/ugly

[marcelstoer]

markdown_extensions:
- toc:
#    permalink: True # renders ¶ sign
    permalink: '#'

Renders permalinks next to h elements but they're static-always-on. The more common behavior found around the internet is they're only displayed on hover.

Inspiriation:

• https://github.com/mkdocs/mkdocs/blob/master/mkdocs/themes/mkdocs/css/base.css#L39
• https://github.com/mkdocs/mkdocs/blob/master/mkdocs/themes/mkdocs/css/base.css#L220-L229