Remove the use of non-existing re.ASCII.

(fixes a regression in 3d46ef0c62c5, issue #18873)

Lib/idlelib/IOBinding.py

@@ -71,7 +71,7 @@ else:
 
 encoding = encoding.lower()
 
-coding_re = re.compile(r'^[ \t\f]*#.*coding[:=][ \t]*([-\w.]+)', re.ASCII)
+coding_re = re.compile(r'^[ \t\f]*#.*coding[:=][ \t]*([-\w.]+)')
 
 class EncodingMessage(SimpleDialog):
     "Inform user that an encoding declaration is needed."

Lib/lib2to3/pgen2/tokenize.py

@@ -236,7 +236,7 @@ class Untokenizer:
                 startline = False
             toks_append(tokval)
 
-cookie_re = re.compile(r'^[ \t\f]*#.*coding[:=][ \t]*([-\w.]+)', re.ASCII)
+cookie_re = re.compile(r'^[ \t\f]*#.*coding[:=][ \t]*([-\w.]+)')
 
 def _get_normal_name(orig_enc):
     """Imitates get_normal_name in tokenizer.c."""

Tools/scripts/findnocoding.py

@@ -32,7 +32,7 @@ except ImportError:
                          "no sophisticated Python source file search will be done.")
 
 
-decl_re = re.compile(r'^[ \t\f]*#.*coding[:=][ \t]*([-\w.]+)', re.ASCII)
+decl_re = re.compile(r'^[ \t\f]*#.*coding[:=][ \t]*([-\w.]+)')
 
 def get_declaration(line):
     match = decl_re.match(line)