IS_URL is true if the string is a URL.
e.g. https://example.invalid is true
function y = is_url(s) y = startsWith(s, alphanumericsPattern + "://"); end %!testif 0
e.g. https://example.invalid is true
function y = is_url(s) y = startsWith(s, alphanumericsPattern + "://"); end %!testif 0