[doc] fix warnings while generate javadoc links

This is due to changed project structure in pmd-scala

docs/_plugins/javadoc_tag.rb

@@ -226,6 +226,11 @@ class JavadocTag < Liquid::Tag
   def self.fqcn_type(artifact_id, fqcn)
 
     artifact_dir = File.join(BASE_PMD_DIR, artifact_id)
+    # special case for scala as we have a different directory structure there
+    if artifact_id =~ /scala/
+      artifact_dir = File.join(BASE_PMD_DIR, "pmd-scala-modules/pmd-scala-common")
+    end
+
     src_dirs = [
         File.join(artifact_dir, "src", "main", "java"),
         File.join(artifact_dir, "target", "generated-sources", "javacc")

docs/_plugins/jdoc_namespace_tag.rb

@@ -86,9 +86,14 @@ class JDocNamespaceDeclaration < Liquid::Tag
       expanded_fqcn += "." + fqcn_suffix
     end
 
+    artifactId = resolved_nspace.first
+
+    if artifactId =~ /scala/
+      artifactId = "pmd-scala_2.13"
+    end
 
     # Return the resolved artifactId + the expanded FQCN
-    [resolved_nspace.first, expanded_fqcn]
+    [artifactId, expanded_fqcn]
   end
 
   private