Support for above-code labels

[jjl]

I have been thinking about how to make nice errors for using builtins in the lisp for my in-progress build tool, dull. At first i copied the structure of the example output image (in wonderfully shit ascii art lol), but it occurred to me that it would be nice to put the reasons above so that they read in order.

ParameterError

 +-[great.dull:1:16]
  |            +- After this scoop indicator
  |            | +- and this scoop parameter
  |            | | +- There should be no more arguments
  |            _ _ _
1 | (defn foo [& _ _])

How does this fit into your plans for layout?

[zesterer]

Oh, that's an interesting idea for sure! I didn't consider that. I think I'll add this to my todo list for the refactor of Ariadne I'm planning to do soon.

[Lokathor]

I looked at the screenshot and wanted this after like 5 seconds, another vote for it.