assert(!`A`.isCapitalizedASCII);
assert(!`a`.isCapitalizedASCII);
assert(!`alpha`.isCapitalizedASCII);
assert(!`ALPHA`.isCapitalizedASCII);
assert(!`aThing`.isCapitalizedASCII);
assert(`Alpha`.isCapitalizedASCII);
assert(`Jack London`.isCapitalizedASCII);
Check if s starts with a capital letter followed by a lower letter.