Merge pull request rails#33953 from wagurano/guides_markdown_custom_header_id

Fix rails guides markdown.rb and renderer.rb to use custom header id

Author: rafaelfranca

guides/rails_guides/markdown.rb

@@ -103,7 +103,7 @@ def generate_structure
                   hierarchy = hierarchy[0, 3] + [node]
                 end
 
-                node[:id] = dom_id(hierarchy)
+                node[:id] = dom_id(hierarchy) unless node[:id]
                 node.inner_html = "#{node_index(hierarchy)} #{node.inner_html}"
               end
             end

guides/rails_guides/markdown/renderer.rb

@@ -29,7 +29,12 @@ def header(text, header_level)
         # Always increase the heading level by 1, so we can use h1, h2 heading in the document
         header_level += 1
 
-        %(<h#{header_level}>#{text}</h#{header_level}>)
+        header_with_id = text.scan(/(.*){#(.*)}/)
+        unless header_with_id.empty?
+          %(<h#{header_level} id=#{header_with_id[0][1].strip}>#{header_with_id[0][0].strip}</h#{header_level}>)
+        else
+          %(<h#{header_level}>#{text}</h#{header_level}>)
+        end
       end
 
       def paragraph(text)