DocumentHighlight for registers as well as other variables?

[themkat]

DocumentHightlight currently highlights symbols like constants and variables like a charm. To me, it would be great if registers could get the same highlighting of symbols as well. Meaning that d0 is marked all places in buffer it is used.

Just to be clear, it is this document highlight I'm referring to:

(here for a symbol COLOR00)

Here we have the cursor at a1, but no highlight:

I think it would be awesome to have the registers highlighted as well. Is this something you would accept if I made a PR? 😄