ediff highlight sub-line differences in non-current sections?

[Ian Kelling]

By default, the non-current diff sections are just gray, but the current
ones has different highlight for the differences within a line.

It would be nice if all sections had the diff highlighting within lines.

I looked into this over a year ago, and it seemed it wasn't implemented.
I'm tempted to dive into the source, but I'm curious what anyone else
might know.