Invalid error throws exception rather than returning valid error back to user.

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I have a form with a date input. Passing a non date value e.g. "1" returns a suitable error back to the user. Entering "2019-22-22" (also an invalid date) results in an exception being thrown. I would expect the second input to return the same error back to the user as the first.

I believe the issue lies in ```time_extensions.cr``` specifically ```try_parsing_with_default_formatters```. This iterates through a series of format options (specified in ```TIME_FORMATS```) attempting to format the given date value. There is a try/catch block which expects a ```Time::Format::Error``` to be thrown if the conversion goes wrong. It looks like (to my untrained eye) that one of the formats (```Time::Format::ISO_8601_DATE```) doesn't appear to throw this exception.

Start in time_extensions.cr at try_parsing_with_default_formatters and inspect the TIME_FORMATS iteration, especially Time::Format::ISO_8601_DATE. Reproduce the inputs "1" and "2019-22-22"; done means both invalid dates return the expected user-facing error instead of allowing an exception to escape.

Written by the indexing model from the issue text.