chore: update ndg and fix linkcheck

docs/manual.nix

@@ -2,43 +2,57 @@
   inputs,
   path,
   stdenvNoCC,
-  runCommandLocal,
   optionsJSON,
-  release,
+  jaq,
 } @ args: let
   manual-release = args.release or "unstable";
 in
-  runCommandLocal "nvf-docs-html" {
+  stdenvNoCC.mkDerivation (finalAttrs: {
+    pname = "nvf-docs-html";
+    version = manual-release;
+    src = ./manual;
+
     nativeBuildInputs = [
-      (inputs.ndg.packages.${stdenvNoCC.system}.ndg.overrideAttrs
-        {
-          # FIXME: the tests take too long to build
-          doCheck = false;
-        })
+      (inputs.ndg.packages.${stdenvNoCC.system}.ndg.overrideAttrs {
+        # FIXME: the tests take too long to build
+        doCheck = false;
+      })
+      jaq
     ];
-  } ''
-    mkdir -p $out/share/doc
 
-    # Copy the markdown sources to be processed by ndg. This is not
-    # strictly necessary, but allows us to modify the Markdown sources
-    # as we see fit.
-    cp -rvf ${./manual} ./manual
+    patchPhase = ''
+      # Replace variables following the @VARIABLE@ style in the manual
+      # pages. This can be built into ndg at a later date.
+      substituteInPlace index.md \
+        --subst-var-by NVF_VERSION ${finalAttrs.version}
 
-    # Replace variables following the @VARIABLE@ style in the manual
-    # pages. This can be built into ndg at a later date.
-    substituteInPlace ./manual/index.md \
-      --subst-var-by NVF_VERSION ${manual-release}
+      language_options=$(cat "${optionsJSON}/share/doc/nixos/options.json" | jaq -r 'keys
+        | map(select(test("^vim\\.languages\\.[^.]+\\.enable$")))
+        | map("- {option}`" + . + "`")
+        | join("\n")'
+      )
 
-    # Generate the final manual from a set of parameters. This uses
-    # feel-co/ndg to render the web manual.
-    ndg --config-file ${./ndg.toml} html \
-      --jobs $NIX_BUILD_CORES --title "NVF" \
-      --module-options ${optionsJSON}/share/doc/nixos/options.json \
-      --manpage-urls ${path}/doc/manpage-urls.json \
-      --input-dir ./manual \
-      --output-dir "$out/share/doc"
+      substituteInPlace configuring/languages.md \
+        --subst-var-by NVF_LANGUAGES_ENABLE "$language_options"
+    '';
 
-    # Hydra support. Probably not necessary.
-    mkdir -p $out/nix-support/
-    echo "doc manual $dest index.html" >> $out/nix-support/hydra-build-products
-  ''
+    buildPhase = ''
+      # Generate the final manual from a set of parameters. This uses
+      # feel-co/ndg to render the web manual.
+      ndg --config-file ${./ndg.toml} html \
+        --jobs $NIX_BUILD_CORES --title "NVF" \
+        --module-options ${optionsJSON}/share/doc/nixos/options.json \
+        --manpage-urls ${path}/doc/manpage-urls.json \
+        --input-dir . \
+        --output-dir build
+    '';
+
+    installPhase = ''
+      mkdir -p $out/share/doc
+      cp -r build/* $out/share/doc/
+
+      # Hydra support. Probably not necessary.
+      mkdir -p $out/nix-support/
+      echo "doc manual $out/share/doc index.html" >> $out/nix-support/hydra-build-products
+    '';
+  })