docs: minor cleanup for change that didn't help

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

docs/_includes/head_custom.html

@@ -8,24 +8,20 @@
 ></script>
 
 <script
-  type="text/javascript"
   src="https://unpkg.com/react@18/umd/react.production.min.js"
   crossorigin
 ></script>
 <script
-  type="text/javascript"
   src="https://unpkg.com/react-dom@18/umd/react-dom.production.min.js"
   crossorigin
 ></script>
 <script
-  type="text/javascript"
   src="https://unpkg.com/@mui/[email protected]/umd/material-ui.production.min.js"
   crossorigin
 ></script>
 
 <!-- pre-processor -->
 <script
-  type="text/javascript"
   src="https://unpkg.com/babel-standalone/babel.min.js"
   crossorigin
 ></script>