more methods: ports, chars

[jrvidal]

This started as "let's add some missing R⁷RS stuff" and ended up a little all over the place :sweat_smile:

TODO

• [x] xtask docgen

[jrvidal]

Just a question, otherwise I think this is good to go!

Cool, let me run docgen before merging (plus maybe take a last look/add some more tests)