Fix python warnings about regexp escape sequences

Author: winterheart

test/normalize.py

@@ -18,7 +18,7 @@ class HTMLParseError(Exception):
 # Normalization code, adapted from
 # https://github.com/karlcow/markdown-testsuite/
 significant_attrs = ["alt", "href", "src", "title"]
-whitespace_re = re.compile('\s+')
+whitespace_re = re.compile(r"\s+")
 class MyHTMLParser(HTMLParser):
     def __init__(self):
         HTMLParser.__init__(self)
@@ -176,7 +176,7 @@ def normalize_html(html):
         '\u2200&><"'
 
     """
-    html_chunk_re = re.compile("(\<!\[CDATA\[.*?\]\]\>|\<[^>]*\>|[^<]+)")
+    html_chunk_re = re.compile(r"(\<!\[CDATA\[.*?\]\]\>|\<[^>]*\>|[^<]+)")
     try:
         parser = MyHTMLParser()
         # We work around HTMLParser's limitations parsing CDATA