Merge branch 'relative-markdown-links' into 'master'

Add support for relative links starting with ./ or / to RelativeLinkFilter

## What does this MR do?

- Allow explicit relative links in Markdown (starting with `./`).
- Allow absolute links (relative to the branch's root directory) in Markdown (starting with `/`).

## Why was this MR needed?

Those link types were not supported before.

## What are the relevant issue numbers?

fixes #19028

See merge request !5586

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/banzai/filter/relative_link_filter.rb b/lib/banzai/filter/relative_link_filter.rb
index 337fb50317d..5b73fc8fcee 100644
--- a/lib/banzai/filter/relative_link_filter.rb
+++ b/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!('../', '')