remove polyfill (#740)

Co-authored-by: lukaspie <lukaspie@github.com>

Author: lukaspie

mkdocs.yaml

@@ -103,5 +103,4 @@ extra_css:
 
 extra_javascript:
   - javascript.js
-  - https://polyfill.io/v3/polyfill.min.js?features=es6
   - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js