Check if s is a lowercased ASCII string.
ditto
assert(!`A`.isLowercasedASCII); assert(`a`.isLowercasedASCII); assert(`alpha`.isLowercasedASCII); assert(!`ALPHA`.isLowercasedASCII); assert(!`aThing`.isLowercasedASCII); assert(!`Alpha`.isLowercasedASCII); assert(!`Jack London`.isLowercasedASCII);
See Implementation
Check if s is a lowercased ASCII string.