Automatically update links when copy/pasting between markdown files

[mjbvz]

Tracks automatically rewriting links in text that is copy and pasted between markdown files. This includes fixing the paths on relative links and also bringing along link definitions if references are copied

[Evileoo]

This is genius ! Spent hours writing docs in markdown and never thought of this 😂

[mjbvz]

Will ship as experimental in April. Moving to may to track finalization if everything looks good