Merge branch 'patch-49' into 'master'

No leading/trailing spaces when generating heading ids (Fixes #57528)

Closes #57528

See merge request gitlab-org/gitlab-ce!27025

changelogs/unreleased/patch-49.yml

+---
+title: Remove leading / trailing spaces from heading when generating header ids
+merge_request: 27025
+author: Willian Balmant
+type: fixed

lib/banzai/filter/table_of_contents_filter.rb

@@ -31,6 +31,7 @@ module Banzai
           if header_content = node.children.first
             id = node
               .text
+              .strip
               .downcase
               .gsub(PUNCTUATION_REGEXP, '') # remove punctuation
               .tr(' ', '-') # replace spaces with dash

spec/lib/banzai/filter/table_of_contents_filter_spec.rb

@@ -58,6 +58,11 @@ describe Banzai::Filter::TableOfContentsFilter do
         expect(doc.css('h1 a').first.attr('href')).to eq '#this-header-is-filled-with-punctuation'
       end
 
+      it 'removes any leading or trailing spaces' do
+        doc = filter(header(1, " \r\n\tTitle with spaces\r\n\t "))
+        expect(doc.css('h1 a').first.attr('href')).to eq '#title-with-spaces'
+      end
+
       it 'appends a unique number to duplicates' do
         doc = filter(header(1, 'One') + header(2, 'One'))