`hsl` doesn't behave the same way in Edge as in Chrome

This breaks some dweets in Edge, for instance https://www.dwitter.net/d/9098

Maybe another Edge-fix to deal with this?

Thanks to u/mvs202 for raising this! He believes it is the 4th parameter of `hsl` not behaving properly in Edge, and automatically changing it to `hsla` might be a fix.

Reproduce dweet 9098 in Edge and Chrome, then inspect how its fourth hsl parameter is handled. Compare the rendering and verify that the affected dweet behaves consistently in both browsers; the issue does not name a source file or test.

Written by the indexing model from the issue text.