2.12.0

CHANGES:

• Add support for OCaml 5.1 (#421, @emillon)

• Mark prompt_continue, prompt_comment, smart_accept, new_prompt_hooks,
  at_new_prompt as deprecated (they have been documented as such since 2012
  and most of them are ignored) (#415, @emillon)

• Qualify () constructor in generated expressions. (#418, fixes #417, @emillon)