Escaped markdown not interpreted as shortcuts

Changelog: added

config/feature_flags/development/honor_escaped_markdown.yml

----
-name: honor_escaped_markdown
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/45922
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/300531
-milestone: '13.9'
-type: development
-group: 'group::project management'
-default_enabled: false

lib/banzai/filter/markdown_pre_escape_filter.rb

@@ -30,8 +30,6 @@ module Banzai
       LITERAL_KEYWORD      = 'cmliteral'
 
       def call
-        return @text unless Feature.enabled?(:honor_escaped_markdown, context[:group] || context[:project]&.group)
-
         @text.gsub(ASCII_PUNCTUATION) do |match|
           # The majority of markdown does not have literals.  If none
           # are found, we can bypass the post filter

spec/lib/banzai/pipeline/plain_markdown_pipeline_spec.rb

@@ -17,20 +17,6 @@ RSpec.describe Banzai::Pipeline::PlainMarkdownPipeline do
       result
     end
 
-    context 'when feature flag honor_escaped_markdown is disabled' do
-      before do
-        stub_feature_flags(honor_escaped_markdown: false)
-      end
-
-      it 'does not escape the markdown' do
-        result = described_class.call(%q(\!), project: project)
-        output = result[:output].to_html
-
-        expect(output).to eq('<p data-sourcepos="1:1-1:2">!</p>')
-        expect(result[:escaped_literals]).to be_falsey
-      end
-    end
-
     describe 'CommonMark tests', :aggregate_failures do
       it 'converts all reference punctuation to literals' do
         reference_chars = Banzai::Filter::MarkdownPreEscapeFilter::REFERENCE_CHARACTERS