Removed reference to js file in conf.py

Author: DoNguyenHung

doc/source/conf.py

@@ -297,10 +297,6 @@
     "css/pandas.css",
 ]
 
-html_js_files = [
-    'js/custom-copy.js'
-]
-
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
 # pixels large.