Exclude index and download page from EPUB build (they are not used)

Author: m-aciek

Doc/conf.py

@@ -512,6 +512,7 @@
 
 epub_author = 'Python Documentation Authors'
 epub_publisher = 'Python Software Foundation'
+epub_exclude_files = ('index.xhtml', 'download.xhtml')
 
 # index pages are not valid xhtml
 # https://github.com/sphinx-doc/sphinx/issues/12359