Add %page_*% replacements for Markdown files
Add %page_*% replacements for Markdown files

`%page_id%` is replaced by the page's ID, `%page_url%` by the page's relative URL, and `%page_path%` by the dirname of page file.

PhrozenByte/Pico,PhrozenByte/Pico,PhrozenByte/Pico