Difference Review, Improve Voice Over

[roblourens]

Testing #186213

Maybe this is related to #186402, but as I tried it I got different results from that mode but it never seemed to read what I expected

I enable screenreader mode and voiceover, and every time I press F7, this is what it reads. I don't really know what the first part is telling me, and also it says "7 lines changed" but this was a file with 2 change chunks, each with just one changed line, so no idea where it is getting 7.

[roblourens]

I guess it's telling me that I can use those commands on the current chunk, but it should read the current chunk, possibly first. Also I don't know what "9 items" refers to

[hediet]

I fixed #186402 and compared the new editor with the old editor. It seems they generate the same voiceover.
I think the voice over is not great and needs improvement, but at least it is not a regression.

[hediet]

This is what I get (pressed F7 and then arrow down):

Difference review. Use "Stage | Unstage | Revert Selected Ranges" commands  list
Difference 1 of 1: original line 638, 7 lines changed, modified line 638, 7 lines changed  1 of 9  level 1
 header.appendChild(cell); unchanged line 638  2 of 9  level 1

[hediet]

Now it says this:

Accessible Diff Viewer. Use arrow up and down to navigate.  list
Difference 3 of 5: original line 101, 18 lines changed, modified line 101, 17 lines changed  1 of 30  level 1