Improvements

[pepeiborra]

Summary

I used debug-pp to instrument hlint with debug-hoed and debug (although I'm no longer able to instrument hlint with debug). During the process I ran into some issues and performance bottlenecks, which I've tried to address in this PR.

Changes

• Switch to Text - debug traces can get pretty large and something more compact than String is required; we need Text to generate JSON anyway, so it seems like the obvious choice. Not user visible anyway.
• Added debugRun - a wrapper for the main function that opens a web browser after the program is run.
• Format call variables using <pre> for slightly nicer rendering and newline preservation
• Fixes for the handling of var bindings in the TH wrapper - do we really want to wrap them all or only the lhss of where clauses ?
• Fixes for the handling of type signatures - I don't think it is possible to add partial constraints (or Show constraints for that matter) to rank-2 arguments without breaking the callers.
• Improved performance of toJSON implementations.

[ndmitchell]

Thanks! I see you also moved to prettyprinter - was that also performance motivated?

[pepeiborra]

Yes, I forgot to mention that. It was part of the switch to text.

[ndmitchell]

Thanks, looks good!