Explicitly set the html parser to make sure no extra tags get added.

BeautifulSoup supports multiple html parsers. Some of those parsers
try to make the html valid by adding/removing tags[1]. This can lead
to useless html, head & body tags in the final document. By explicitly
setting the parser to ’html.parser’ this behaviour can be avoided.

[1] http://www.crummy.com/software/BeautifulSoup/bs4/doc/#differences-between-parsers

extract_toc/extract_toc.py

@@ -14,7 +14,7 @@ from pelican import signals, readers, contents
 def extract_toc(content):
     if isinstance(content, contents.Static):
         return
-    soup = BeautifulSoup(content._content)
+    soup = BeautifulSoup(content._content,'html.parser')
     filename = content.source_path
     extension = path.splitext(filename)[1][1:]
     toc = ''