Add support for relative links starting with ./ or / to RelativeLinkFilter (!5586)

CHANGELOG

@@ -4,6 +4,7 @@ v 8.11.0 (unreleased)
   - Fix the title of the toggle dropdown button. !5515 (herminiotorres)
   - Improve diff performance by eliminating redundant checks for text blobs
   - Remove magic comments (`# encoding: UTF-8`) from Ruby files. !5456 (winniehell)
+  - Add support for relative links starting with ./ or / to RelativeLinkFilter (winniehell)
   - Fix CI status icon link underline (ClemMakesApps)
   - Cache the commit author in RequestStore to avoid extra lookups in PostReceive
   - Fix of 'Commits being passed to custom hooks are already reachable when using the UI'

lib/banzai/filter/relative_link_filter.rb

@@ -87,10 +87,13 @@ module Banzai
       def build_relative_path(path, request_path)
         return request_path if path.empty?
         return path unless request_path
+        return path[1..-1] if path.start_with?('/')
 
         parts = request_path.split('/')
         parts.pop if uri_type(request_path) != :tree
 
+        path.sub!(%r{^\./}, '')
+
         while path.start_with?('../')
           parts.pop
           path.sub!('../', '')