[css-grid] proposal for repeat to take a third argument for jointure

TLDR: why not “repeat(<int>,  (col-start) 100px (col-end),  10px)” ==> “(col-start) 100px (col-end)  10px ... 10px  (col-start) 100px (col-end)”?

Reasoning: otherwise, if we want to replicate this behavior, we have to write “(col-start) 100px (col-end) repeat(<int-1>, 10px (col-start) 100px (col-end))” which is counter-intuitive (and I remember we thought it was annoying to have to define “function(<length> [, <length>]*)” instead of “function([<length>]{,}+)” and this seems like a similar issue here).

Thoughts?