fix(lang): stop internal book ids reaching output, and finish the docs

Three defects, all found by running the documented examples rather than
by reading code.

All seven modern-numbering targets carried their own internal id as
their Latin name (kings_1.full = kings_1), so --sigla-tradition modern
printed "kings_1 19:3-8" -- leaking a key book.mli states is never shown
to a reader. They now carry Vulgate-derived Latin names marked
CONSTRUCTED: the 1962 Missal uses Vulgate numbering throughout, so it
can contain no incipit for a book that exists only under a later
convention. In Latin the modern tradition therefore only moves Kings and
Esdras; Osee, Ionas, Ecclesiasticus and the Apocalypse keep their names
either way, since modern numbering is a vernacular convention.

The coverage test could not catch this. It compares a name against its
KEY ("kings_1.full"), and "kings_1" differs from that, so the row
passed. A second check now asserts no name IS its own id. The two are
complementary: one catches a missing row, the other a row present but
filled with the wrong thing. Mutation-proved.

--help still claimed sigla settings were resolved "but not yet
rendered", stale since the render wiring landed. colitur-config.5
documented none of the three settings even though config --show prints
them.

1 files changed, 28 insertions, 0 deletions

diff --git a/test/test_lang_coverage.ml b/test/test_lang_coverage.ml
index b2d32a4..0271a59 100644
--- a/test/test_lang_coverage.ml
+++ b/test/test_lang_coverage.ml
@@ -119,6 +119,32 @@ let test_every_book_named () =
   in
   Alcotest.(check (list string)) "every book named, both forms" [] missing
 
+(* A name must not BE the internal id. The check above compares the value
+   against the KEY ("kings_1.full"), so a row reading `kings_1.full = kings_1`
+   passes it -- the two strings differ. That is exactly what shipped: all seven
+   tradition targets carried their own id as their name, and
+   `--sigla-tradition modern` printed "kings_1 19:3-8", leaking a key that
+   book.mli states is never shown to a reader.
+
+   The two checks are complementary and neither subsumes the other: that one
+   catches a MISSING row, this one catches a row present but filled with the
+   wrong thing. *)
+let test_no_book_name_is_an_internal_id () =
+  let la = la () in
+  let leaked =
+    List.concat_map
+      (fun id ->
+        let n = Colitur_citation.Book.to_string id in
+        List.filter_map
+          (fun form ->
+            let v = L.bible la (n ^ "." ^ form) in
+            if v = n then Some (n ^ "." ^ form) else None)
+          [ "full"; "abbr" ])
+      Colitur_citation.Book.all
+  in
+  Alcotest.(check (list string)) "no book name is its own internal id" []
+    leaked
+
 (* lang/en.ini is DELIBERATELY partial (see its own header note): it declares
    [meta] fallback = la, so a slug it does not carry itself should still
    resolve through the chain to la.ini's name rather than degrade to the bare
@@ -161,4 +187,6 @@ let suite =
       Alcotest.test_case "vocabularies complete" `Quick test_vocabularies_are_complete;
       Alcotest.test_case "every rite has a Latin name" `Quick test_every_rite_has_a_latin_name;
       Alcotest.test_case "every book named, both forms" `Quick test_every_book_named;
+      Alcotest.test_case "no book name is an internal id" `Quick
+        test_no_book_name_is_an_internal_id;
       Alcotest.test_case "en.ini falls back to Latin" `Quick test_en_falls_back_to_latin ] )