Trailing dot should be concatenated, according to PSL algorithm & WHATWG URL standard

[ukusormus]

PSL algorithm, https://github.com/publicsuffix/list/wiki/Format#note-3:

Note 3
[...] looking up example.com should yield com while looking up example.com. should yield com. as the public suffix.

WHATWG URL standard, https://url.spec.whatwg.org/#host-registrable-domain:

To obtain the registrable domain of a host host, run these steps. [...]
...
2. Let trailingDot be "." if host ends with "."; otherwise the empty string.
...
5. Return registrableDomain and trailingDot concatenated.

Example:
Host input | Public suffix | Registrable domain
example.com. | com. | example.com.

Real-life implementations agree, too: testing out on latest versions of Chrome and Firefox, there's a different cookie jar per domain with and without a trailing dot. See response.ee. proof of concept (try out the same generated response with response.ee and response.ee.).

---

Test code, index.mjs:

import psl from 'psl';

console.log(psl.parse("example.com."))
console.log(psl.get("example.com."))

Current output:

{
  input: 'example.com.',
  tld: 'com',
  sld: 'example',
  domain: 'example.com',
  subdomain: null,
  listed: true
}
example.com

Expected output:

{
  input: 'example.com.',
  tld: 'com.',  // trailing "." added
  sld: 'example',
  domain: 'example.com.',  // trailing "." added
  subdomain: null,
  listed: true
}
example.com.  // trailing "." added

[mfdebian]

Thank you @ukusormus, we'll work on this!