Highlight error part in REPL

[xsebek]

Closes #1956

[xsebek]

@byorgey could you please have a look? It only works to a degree, and I suspect there are bugs:

• This looks OK:
  
• When no location is given it should highlight whole line:
  
• But it seems to suspiciously extend more then it should, so likely made a mistake somewhere:
  

Feel free to push to this branch if you find anything; I am out of ideas for today. 😄

[byorgey]

The part of the prompt being highlighted does not seem correct. It always seems to extend from the beginning of the error all the way to the end of the line, no matter what. For example, when I entered build {(place 2); move } everything from 2 to the closing } is red.

[xsebek]

@byorgey, after reading your comment again, I found the arithmetic bug that extended the range. 👍

[xsebek]

Should work well now. Please have a look.

I hit up through my history and it seemed nicely highlighted.

[byorgey]

Looks great! All the examples I tried seemed nicely highlighted too. Thanks for putting this together, it's a very nice feature!

[nitinprakash96]

Works nicely!