Feature request: match and replacement word highlighting within the replacement preview diff

[LeoniePhiline]

At times, a line contains multiple matches.

Fastmod thus presents the line multiple times, once for each match and replacement within the line.

It can be difficult to see where exactly something is being replaced, especially when replacing matches in very long lines. (think minification test fixtures, but much shorter lines can also benefit from word highlighting)

A rather extreme example (pixellated, but the point should become obvious):

The individual match and replacement should be highlighted within the red and green lines.