removes invalid , from generated html

lib/open_project/text_formatting.rb

@@ -383,7 +383,7 @@ module OpenProject
           div_class = 'toc'
           div_class << ' right' if $1 == '>'
           div_class << ' left' if $1 == '<'
-          out = "<fieldset class='header_collapsible collapsible'><legend title='" + l(:description_toc_toggle)+ "', onclick='toggleFieldset(this);'><a href='javascript:'>#{l(:label_table_of_contents)}</a></legend><div>"
+          out = "<fieldset class='header_collapsible collapsible'><legend title='" + l(:description_toc_toggle)+ "' onclick='toggleFieldset(this);'><a href='javascript:'>#{l(:label_table_of_contents)}</a></legend><div>"
           out << "<ul class=\"#{div_class}\"><li>"
           root = headings.map(&:first).min
           current = root