revert mkdocs changes

mkdocs.yml

@@ -33,13 +33,4 @@ markdown_extensions:
   - pymdownx.details
   - pymdownx.tasklist:
       custom_checkbox: true
-  - pymdownx.arithmatex:
-      generic: true
 
-extra_javascript:
-  - javascripts/katex.js
-  - https://unpkg.com/katex@0/dist/katex.min.js
-  - https://unpkg.com/katex@0/dist/contrib/auto-render.min.js
-
-extra_css:
-  - https://unpkg.com/katex@0/dist/katex.min.css