lint: Do not allow locale dependent shell scripts

Bash is discouraged, and there was never a need to write locale
dependent Bash.

So remove the option and clarify that the LC_ALL settings enable UTF-8
mode in Python.

test/lint/lint-shell-locale.py

@@ -1,22 +1,19 @@
 #!/usr/bin/env python3
 #
-# Copyright (c) 2018-2022 The Bitcoin Core developers
+# Copyright (c) 2018-present The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 """
-Make sure all shell scripts are:
-a.) explicitly opt out of locale dependence using
-    "export LC_ALL=C" or "export LC_ALL=C.UTF-8", or
-b.) explicitly opt in to locale dependence using the annotation below.
+Make sure all shell scripts explicitly opt out of locale dependence using
+"export LC_ALL=C" or "export LC_ALL=C.UTF-8", which also enables UTF-8 mode in
+Python. See: https://docs.python.org/3/library/os.html#python-utf-8-mode
 """
 
 import subprocess
 import sys
 import re
 
-OPT_IN_LINE = '# This script is intentionally locale dependent by not setting \"export LC_ALL=C\"'
-
 OPT_OUT_LINES = [
     'export LC_ALL=C',
     'export LC_ALL=C.UTF-8',
@@ -47,9 +44,6 @@ def main():
         with open(file_path, 'r', encoding='utf-8') as file_obj:
             contents = file_obj.read()
 
-        if OPT_IN_LINE in contents:
-            continue
-
         non_comment_pattern = re.compile(r'^\s*((?!#).+)$', re.MULTILINE)
         non_comment_lines = re.findall(non_comment_pattern, contents)
         if not non_comment_lines: