Ignore newline vs space

[walles]

If a newline is replaced with a space character, or a space character is replaced with a newline, don't highlight this.

This is what happens when rewrapping text, and I think highlighting these changes doesn't help me understand what's going on.

Also consider what this would mean for indented text being rewrapped.

[walles]

As long as distil/diffus#107 is still a thing we can't identify replacements (I think?), and this is not doable.

[walles]

Or, we could just unhighlight this in post processing.

[walles]

Done, out in 3.3.5!