letfn is a macro over a letfn* special form (Clojure semantics)

jolt modelled letfn as a special form directly, so (macroexpand-1 '(letfn …))
returned the form unchanged. Clojure's letfn is a macro that expands to letfn*,
and macroexpansion tooling (tools.macro, tools.analyzer) depends on that — its
special-form handlers key on letfn*, not letfn.

Split it the Clojure way:
- letfn* is now the special form (analyzer), taking flat name/fn-form pairs
  [name1 fn1 name2 fn2 …] — the letrec :let lowering is unchanged.
- letfn is a macro (00-syntax) turning each (name [params] body*) spec into a
  name + (fn name [params] body*) binding, so it expands to letfn*.

So (macroexpand-1 '(letfn [(f [x] x)] (f 1))) now yields
(letfn* [f (fn f [x] x)] (f 1)), and clojure.tools.macro passes its whole suite
(macrolet / symbol-macrolet / mexpand-all). Listed in docs + site.

make test green (+1 corpus row, 0 new divergences), shakesmoke byte-identical.
One re-mint (analyzer + the letfn macro); selfhost holds.

docs/libraries.md

@@ -65,6 +65,8 @@ e.g. the [ring-app example](https://github.com/jolt-lang/examples/tree/main/ring
   byte arrays.
 * [data.priority-map](https://github.com/clojure/data.priority-map) — priority
   maps (incl. keyfn / custom comparator), with `subseq`/`rsubseq`.
+* [tools.macro](https://github.com/clojure/tools.macro) — local macros
+  (`macrolet`/`symbol-macrolet`), `mexpand`/`mexpand-all`.
 * [test.check](https://github.com/clojure/test.check) — property-based testing
   (generators, `quick-check`, shrinking).
 * [tick](https://github.com/juxt/tick) — date/time over Jolt's `java.time`;