Reference Link component: Automatically use the icon of the target

[paralexm]

When using a reference link component, it automatically uses the label of the .md page as the link text. It would be very helpful if it could also automatically use the icon too.

With this getting-started.md:

---
icon: rocket
---
# Getting Started

A reference link specified like this:

[!ref](getting-started.md)

Would look like this:

[geoffreymcgill]

Very good idea. We should be able to get this working.