removing js files not used anymore

Author: lidiazuin

src/js/80-research.js

@@ -22,5 +22,4 @@ import './25-graphgist'
 import './40-challenges'
 import './50-cheat-sheet-toggle'
 import './60-docs-roles'
-import './70-docs-ndl'
-import './80-research'
+import './70-docs-ndl'