Inspired by Terraform's error output, the box drawing characters tend
to get connected in a terminal (but not IntelliJ it seems), it looks
slightly cleaner than pipes. And these code points are in Unicode since
1993, so I don't think they are particularly controversial to use
(unlike color emoji).
And now that I have to rewrite all the goldens, let's fix the column
counter too. It still counts bytes and not columns, but I'm not sure
if the way it's counted is consistent across applications. We could
the existing unicode-width dependency to count though.
Previously this was difficult to do, because the abstractor could not
report errors. But in the meantime I added that, so now this is every
easy to do. Nice, one more todo eliminated!
Handling numbers with a decimal point (floats) is still to be done
though.
