markdown: fixed sanitization of checkbox extensions that removed "checked" attribute.

- Fixes  #5513

rhodecode/lib/bleach_whitelist.py

@@ -70,7 +70,7 b' markdown_attrs = {'
     "abbr": ["title"],
     "acronym": ["title"],
     "pre": ["lang"],
-    "input": ["type", "disabled"]
+    "input": ["type", "disabled", "checked"]
 }
 
 standard_styles = [

rhodecode/lib/markdown_ext.py

@@ -18,26 +18,11 b''
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
-import re
-
 import markdown
 
 from mdx_gfm import GithubFlavoredMarkdownExtension  # pragma: no cover
 
 
-class FlavoredCheckboxPostprocessor(markdown.postprocessors.Postprocessor):
-    """
-    Adds `flavored_checkbox_list` class to list of checkboxes
-    """
-
-    pattern = re.compile(r'^([*-]) \[([ x])\]')
-
-    def run(self, html):
-        before = '<ul>\n<li><input type="checkbox"'
-        after = '<ul class="flavored_checkbox_list">\n<li><input type="checkbox"'
-        return html.replace(before, after)
-
-
 # Global Vars
 URLIZE_RE = '(%s)' % '|'.join([
     r'<(?:f|ht)tps?://[^>]*>',