Update Docs::Rdoc::CleanHtmlFilter to properly set the source section link when generated from Ruby 3.4+

Author: StalemateInc

lib/docs/filters/rdoc/clean_html.rb

@@ -30,12 +30,24 @@ def other
           node.remove_attribute 'id'
         end
 
-        # Convert "click to toggle source" into a link
+        # (RDoc prior to Ruby 3.4) Convert "click to toggle source" into a link
         css('.method-click-advice').each do |node|
           node.name = 'a'
           node.content = 'Show source'
         end
 
+        # (RDoc for Ruby 3.4+) Add a "Show source" link
+        css('.method-source-toggle').each do |node|
+          link_node = Nokogiri::XML::Node.new('a', doc.document)
+          link_node.content = 'Show source'
+          link_node['class'] = 'method-click-advice'
+
+          node.parent.parent.at_css('.method-heading').add_child(link_node)
+        end
+
+        # (RDoc for Ruby 3.4+) Remove the additional "Source" toggle from the page
+        css('.method-controls').remove
+
         # Add class to differentiate Ruby code from C code
         css('.method-source-code').each do |node|
           node.parent.prepend_child(node)