autoprefixer: Add Warning when grid-gap could not be Transpiled for IE

In #1032, grid-gap support was introduced in order to support IE. It only works though when grid-template-areas, grid-template-rows and grid-template-columns are provided in the same rule. Since this is a hard to spot IE problem, it would be very helpful to output Warnings when grid-gap could not be translated for IE (and maybe even an Error #1165). Would that be possible?

About this issue

Yep, I can confirm that grid-column-gap and grid-row-gap do not trigger the grid-gap warning.

Ahh ok, @ai this is probably a valid bug then.

I was using grid-column-gap and grid-row-gap separately:

.blah {
  grid-template-areas: 'left right';
  grid-template-columns: auto 1fr;
  grid-template-rows: auto;
  grid-column-gap: 10px;
}