Patterns starting with "/" (e.g. /docs/.*\.md) never matched because git
returns relative paths without a leading slash. Strip the leading "/"
before compiling the regex since the ^...$ anchoring already provides
root-relative semantics.
Fixes: #28107
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Giteabot <teabot@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>