Migrate XdocGenerator to Doxia Sink API with XDOC 2.0 output

Co-authored-by: slachiewicz <6705942+slachiewicz@users.noreply.github.com>

Author: Copilot

modello-plugins/modello-plugin-xdoc/pom.xml

@@ -25,6 +25,16 @@
       <groupId>org.codehaus.plexus</groupId>
       <artifactId>plexus-utils</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.apache.maven.doxia</groupId>
+      <artifactId>doxia-sink-api</artifactId>
+      <version>2.0.0</version>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.maven.doxia</groupId>
+      <artifactId>doxia-module-xdoc</artifactId>
+      <version>2.0.0</version>
+    </dependency>
     <dependency>
       <groupId>org.jsoup</groupId>
       <artifactId>jsoup</artifactId>