Check List

• I have already read Docs page
• I have already searched existing issues

Feature Request

Add a tag plugin for url_for (and full_url_for) helper.

Existing tags plugins

Surprisingly there are post_path and post_link that works only for posts in the source/_posts/ folder and asset_path and asset_link for assets in the post_asset_folder but there is nothing for pages or something more generic.

Issue

So if you wan to refer to source/docs/b.md from source/docs/a.md you can use a classic abosulute link eg. [b](/docs/b) or [b](/docs/b.html) or a classic relative link [b](docs/b).

Classic absolute links won't work when you have a root: /root/ prefix in _config.yml because your link will be /docs/b.html instead of /root/docs/b.html, and relative links won't work if you are not at the root, eg. if you are at /root/docs/ your link will be /root/docs/docs/b.html. That's why url_for and `full_url_for were created in the first place, but they are not available from content.