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

Update based on comments in MR #27025

lib/banzai/filter/table_of_contents_filter.rb

@@ -17,8 +17,8 @@ module Banzai
     #   :toc - String containing Table of Contents data as a `ul` element with
     #          `li` child elements.
     class TableOfContentsFilter < HTML::Pipeline::Filter
-      PUNCTUATION_REGEXP = /[^\p{Word}\- ]/u
-      LEADING_OR_TRAILING_SPACE_REGEXP = /^\p{Space}|\p{Space}$/
+      PUNCTUATION_REGEXP = /[^\p{Word}\- ]/u.freeze
+      LEADING_OR_TRAILING_SPACE_REGEXP = /^\p{Space}+|\p{Space}+$/.freeze
 
       def call
         return doc if context[:no_header_anchors]

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 \t Title 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'))