fix: adoc multipage wrapper includes relfileprefix

Author: alandefreitas

share/mrdocs/addons/generator/adoc/layouts/wrapper.adoc.hbs

@@ -9,7 +9,32 @@
 
     Breadcrumbs are included in the symbol template as an alternative.
 }}
-= {{> symbol/qualified-name symbol nolink=true }}
+= {{> symbol/qualified-name symbol nolink=false }}
+{{!
+    Antora does not support relative links to pages in
+    parent directories. Therefore, unlike in HTML templates,
+    links are not relativized.
+
+    However, while Antora interprets xref as relative
+    to the root of the module, these xref are
+    interpreted as relative to the current directory
+    because it has no concept of modules. This means
+    links would be broken with either Antora or Asciidoc.
+
+    Even more, Antora uses the same rule as Asciidoc
+    for breadcrumbs and the page title, where links
+    would also be broken.
+
+    The solution is to set the relfileprefix attribute,
+    which includes the relative location of the root
+    directory and makes all links relative to it.
+
+    This relfileprefix affects Asciidoc links, the
+    Antora title, and the Antora breadcrumbs.
+
+    See https://docs.asciidoctor.org/asciidoc/latest/macros/inter-document-xref/#mapping-references-to-a-different-structure
+}}
+:relfileprefix: {{{ repeat "../" (count (remove_prefix symbol.url '/') '/') }}}
 {{else}}
 {{! Single page documentation: symbol is not available to the wrapper }}
 = Reference