Move the antora extension to its own directory.

Author: steve-downey

.pre-commit-config.yaml

@@ -42,7 +42,8 @@ repos:
         args: ['-I', '.codespell_ignore', '--uri-ignore-words-list', '*']
         exclude: >
           (?x)^(
-            papers/.*
+            papers/.* |
+            package-lock.json
           )$
 
     # Beman Standard checking via beman-tidy

antora-playbook.yml

@@ -24,7 +24,7 @@ antora:
     # Fixes Antora 3.1's inability to open a local content source whose .git
     # entry is a gitdir file (linked git worktree).  Must come first so the
     # url is corrected before the cpp-reference extension runs.
-    - require: './antora-worktree-fix.js'
+    - require: 'antora/antora-worktree-fix.js'
     - require: '@cppalliance/antora-cpp-reference-extension'
 
 content: