ocaml-atp: add test_naming.ml for hermest/lib/naming.ml (E605)
ocaml-clcw: merge fuzz_diff.ml into fuzz_clcw.ml to fix E710
(fuzz_diff had no corresponding library module)
ocaml-retry: extract test_retry.ml module with suite tuple (E605)

Replace Printf.sprintf with Fmt.str and Printf.printf with Fmt.pr
across requests, retry, and rpmsg test files.

Rename create/make to v in rpmsg, error, proxy, auth, version, and
other modules. Fix doc style issues in error.mli, requests.mli, and
expect_continue.mli. Update all callers.