search match highlighting wrong when whitespaces are to be matched, too.

[christianparpart]

Example search term

Setting render target size

This string contains 3 whitespace characters. And this is the number the match is highlighted too far to the left,
becuase when a match is considered found, we currently simple walk N cells to the left and start recoloring,
even though we did not take whitespace cells into account.

Example output

How to fix

we can't simply recolor, because we also want the whitespace (empty) cells to be colorized, too.
But since they don't exist in the output buffer, we probably need to have a customized codepath not optimizing whitespaces away too much when search terms (/matches) are to be highlighted, in order to get proper highlighting on whitespaces as well as starting on the correct cell.