Determines whether a given text-based value is printable.

Printable example:

    let hello = "hello";
    let is_printable = hello.is_printable();
    assert_eq!(is_printable, true);

Unprintable example:

    let bell = '\u{7}'
    let is_printable = bell.is_printable();
    assert_eq!(is_printable, false);