Remove Show superclass on Alpha

[Jashweii]

This would be a breaking change for anything using show* but constrained only on Alpha. Bind's nthPatFind and namePatFind wouldn't be able to show the specific bind for errors anymore.

• remove (Show a) => (Alpha.hs 160)
• remove (Show t) => (Ignore.hs 35)
• remove " ++ show b ++ " (Bind.hs 66/67)

(These are the changes that I could find.)

[lambdageek]

This is worth exploring. I'd be curious to see a PR that got rid of the Show constraint.