chore: remove unused styles parameter

Surfaced via `mypy`, recommended adding a type to the empty list.

The list was originally empty back in 0.1.0.

Instead of adding a type, remove the constant, and the code that uses it
from `clean()` - as it was partially reverted in pypa#121.

The default `ALLOWED_STYLES` in the underlying library is `[]`.

Related: pypa#114 (comment)

Signed-off-by: Mike Fiedler <miketheman@gmail.com>

readme_renderer/clean.py

@@ -59,9 +59,6 @@
     "input": ["type", "checked", "disabled"],
 }
 
-ALLOWED_STYLES = [
-]
-
 
 class DisabledCheckboxInputsFilter:
     def __init__(self, source):
@@ -89,19 +86,16 @@ def __getattr__(self, name):
         return getattr(self.source, name)
 
 
-def clean(html, tags=None, attributes=None, styles=None):
+def clean(html, tags=None, attributes=None):
     if tags is None:
         tags = ALLOWED_TAGS
     if attributes is None:
         attributes = ALLOWED_ATTRIBUTES
-    if styles is None:
-        styles = ALLOWED_STYLES
 
     # Clean the output using Bleach
     cleaner = bleach.sanitizer.Cleaner(
         tags=tags,
         attributes=attributes,
-        styles=styles,
         filters=[
             # Bleach Linkify makes it easy to modify links, however, we will
             # not be using it to create additional links.