Documentation no longer includes format specifiers (as a bonus, old doc links are all dead)

[dmbaturin]

The old docs used to have useful information on the formats: https://web.archive.org/web/20160415075101/http://calendar.forge.ocamlcore.org/doc/Printer.html

It's no longer the case. The original documentation links don't work anymore, and the new docs leave the user to guess what the available specifiers are.

I can help fix it, but I need to know where you think this info should be in the docs.