check50 bug with CS50P/Wk4/Adieu

[vinter423]

The assignment for Game stipulates that the program should reject "non-positive" guesses, but the only "non-positive" guess check50 tests for is 0 - not any negative numbers. This allows a version of your program that allows negative integer guesses and responds with "Too Small!" every time before reprompting, instead of immediately reprompting as the assignment stipulated it should, while still passing all green :)