Fix missing or wrong shebangs and missing executable bits for scripts (#10318)

Tools/scripts/abitype.py

+#!/usr/bin/env python3
 # This script converts a C file to use the PEP 384 type definition API
 # Usage: abitype.py < old_code > new_code
 import re, sys

Tools/scripts/diff.py

+#!/usr/bin/env python3
 """ Command line interface to difflib.py providing diffs in four formats:
 
 * ndiff:    lists every line and highlights interline changes.

Tools/scripts/mailerdaemon.py

+#!/usr/bin/env python3
 """Classes to parse mailer-daemon messages."""
 
 import calendar

Tools/scripts/make_ctype.py

+#!/usr/bin/env python3
 """Script that generates the ctype.h-replacement in stringobject.c."""
 
 NAMES = ("LOWER", "UPPER", "ALPHA", "DIGIT", "XDIGIT", "ALNUM", "SPACE")

Tools/scripts/patchcheck.py

+#!/usr/bin/env python3
 import re
 import sys
 import shutil

Tools/scripts/reindent-rst.py

-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # Make a reST file compliant to our pre-commit hook.
 # Currently just remove trailing whitespace.