setup antora-cpp-tagfiles-extension

Author: ashtum

doc/antora.yml

@@ -11,3 +11,9 @@ nav:
 ext:
   cpp-reference:
     config: doc/mrdocs.yml
+  cpp-tagfiles:
+    files:
+      - file: ./doc/tagfiles/boost-http_proto-doxygen.tag.xml
+        base_url: 'xref:reference:'
+    using-namespaces:
+      - boost::http_proto