adjust some libraries to avoid converting paths to strings too early

Early conversions leave absolute paths in bytecode and rendered
documentation.

original commit: 9b569aa9a2ea5ac800c6ba50eb4f29452ecc1dd6

collects/rackunit/scribblings/check.scrbl

@@ -3,6 +3,7 @@
 
 @(define rackunit-eval (make-base-eval))
 @(interaction-eval #:eval rackunit-eval (require rackunit))
+@(interaction-eval #:eval rackunit-eval (error-print-context-length 0))
 
 @title{Checks}