This is a port of my original Haskell library Diagnose, which is an error-reporting library. The basic goal is to format errors beautifully while still keeping the easiness of generating them.
Here is an example of what it produces (in the IntelliJ console¹):
⁽¹⁾: Lines are disconnected. This is because IntelliJ spaces characters so much. This should not be the case in most terminals or when outputting as text.