FIX: remove Nokogumbo references (#13951)

FIX: remove Nokogumbo references (#13951)

Specs broken after https://github.com/discourse/discourse/commit/f4720205c0c2ceabc9a277ab957f0374ab154e8c

diff --git a/lib/html_to_markdown.rb b/lib/html_to_markdown.rb
index dbb7f22..d602c2d 100644
--- a/lib/html_to_markdown.rb
+++ b/lib/html_to_markdown.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "nokogumbo"
 require "securerandom"
 
 class HtmlToMarkdown
diff --git a/spec/services/search_indexer_spec.rb b/spec/services/search_indexer_spec.rb
index c890c43..1721b7b 100644
--- a/spec/services/search_indexer_spec.rb
+++ b/spec/services/search_indexer_spec.rb
@@ -145,7 +145,7 @@ describe SearchIndexer do
     end
 
     it 'should work with invalid HTML' do
-      post.update!(cooked: "<FD>" * Nokogumbo::DEFAULT_MAX_TREE_DEPTH)
+      post.update!(cooked: "<FD>" * Nokogiri::Gumbo::DEFAULT_MAX_TREE_DEPTH)
 
       SearchIndexer.update_posts_index(
         post_id: post.id,

GitHub sha: 354c939656553aaa631761e0bdc228b948b7e555

This commit appears in #13951 which was approved by martin. It was merged by SamSaffron.