Don’t use backslashes in f-strings to please Python < 3.12

Author: liZe

tinycss2/color3.py

@@ -142,10 +142,10 @@ def _parse_comma_separated(tokens):
 
 
 _HASH_REGEXPS = (
-    (2, re.compile(f'^{4 * "([\\da-f])"}$', re.I).match),
-    (1, re.compile(f'^{4 * "([\\da-f]{2})"}$', re.I).match),
-    (2, re.compile(f'^{3 * "([\\da-f])"}$', re.I).match),
-    (1, re.compile(f'^{3 * "([\\da-f]{2})"}$', re.I).match),
+    (2, re.compile(f'^{4 * "([0-9a-f])"}$', re.I).match),
+    (1, re.compile(f'^{4 * "([0-9a-f]{2})"}$', re.I).match),
+    (2, re.compile(f'^{3 * "([0-9a-f])"}$', re.I).match),
+    (1, re.compile(f'^{3 * "([0-9a-f]{2})"}$', re.I).match),
 )