Fix html min

Author: Juan Carlos

css_html_js_minify/html_minifier.py

@@ -99,7 +99,7 @@ def remove_html_comments(html):
     """  # Grunt uses comments to as build arguments, bad practice but still.
     log.debug("""Removing all unnecessary HTML comments; Keep all containing:
     'build:', 'endbuild', '<!--[if]>', '<![endif]-->' for Grunt/Grymt, IE.""")
-    return re.compile('<!-- [^(build|endbuild)].*? -->', re.I).sub('', html)
+    return re.compile(r'<!-- [^(build|endbuild)].*? -->', re.I).sub('', html)
 
 
 def unquote_html_attributes(html):