[ issue 1293 ] Renamed qualified name
[ issue 1293 ] Using monadic pretty printer combinators
[ issue 1293 ] Cosmetic changes
[ issue 1293 ] Cosmetic changes
[ issue 1293 ] Renamed functions

showArg -> prettyArg
showPat -> prettyPat
[ issue 1293 ] Added Pretty instances
[ issue 1293 ] Replaced show function by pretty[TCM|Show]
Merge branch 'maint-2.4.2'

Conflicts:
	src/full/Agda/TypeChecking/Errors.hs