New version is unforgiving for trailing spaces

[arokettu]

every '47 */6 * * * ' do
  # ...
end

produces error ArgumentError: Couldn't parse: 47 */6 * * *

My issue was resolved by removing the trailing space manually however it's a backward incompatible change with a misleading error message

[benlangfeld]

The backward compatability is something we have to live with until we cut v1.0, but we can do a better job with the error message by calling #inspect on the value so it would read:

ArgumentError: Couldn't parse: "47 */6 * * * "

Is this something you would be prepared to submit a PR for?