I seem to have switched to a stretch at some point, which isn't ideal and can be
achieved anyway with the stretch option. A two-line crop (1 at top, 1 at bottom)
is generally the better option.
There's now also a hidden ini setting to turn it off. I might be
convinced to add it as a real setting once I figure out a good name for
it. The setting:
```ini
[Graphics]
DisplayCrop16x9 = True
```
Fixes#18693