Add plugin

Author: mborland

doc/decimal-playbook.yml

@@ -10,5 +10,9 @@ output:
   dir: html
 ui:
   bundle:
-    url: https://github.com/boostorg/website-v2-docs/releases/download/ui-master/ui-bundle.zip
+    url: https://gitlab.com/antora/antora-ui-default/-/jobs/artifacts/HEAD/raw/build/ui-bundle.zip?job=bundle-stable
   output_dir: decimal/_
+  supplemental_files: ./supplemental-ui
+antora:
+  extensions:
+    - '@antora/lunr-extension'

doc/package-lock.json

@@ -3,5 +3,8 @@
     "@antora/cli": "3.1.14",
     "@antora/site-generator": "3.1.14",
     "antora": "3.1.14"
+  },
+  "dependencies": {
+    "@antora/lunr-extension": "^1.0.0-alpha.12"
   }
 }