Users often want to put UI elements like "links to social media" in the parts of our UI that we populate with "site parts". ie, a user defines a markdown file, that file is parsed to AST and then inserted into the part.

We could thus enable icons in site parts by defining a role that users could use to define these links. It would be a simpler way of providing standard icon images rather than hand-including images with their sites.

For example:

# In sidebar_footer.md
{icon}`foo <https://mylink>` {icon}`github`