Toolbox-like handling of long error trace record differences

[JoshuaRowePhantom]

tlaplus#127 describes long error trace records not being easily viewable. I still find this the case: the copy-to-clipboard feature is a bit cumbersome to use.

A feature I found very valuable in the Toolbox was the highlighting of differences between states. This feature has become much more subtle in the VsCode version. I can see that a complete variable has been modified, but for e.g. a function the Toolbox would highlight domain entries whose value had been modified where VsCode does not. This recurse exploration of modified values is itself a very valuable feature. Further, this can help solve the issue in #127 by allowing recursive expansion of values.

Allowing recursive exploration of the error trace values and highlighting the changes values would bring the error trace up to par with the Toolbox.

[JoshuaRowePhantom]

I also meant to say that the view value feature is a little cumbersome. Opening a new text editor for every value then requires user action to close it, and it tends to hide the work the user is doing. Maybe there's a better workflow I could try, but really the recursive explorer with built-in long value viewing would work out-of-the-box much better for me.