fix(quiz1): Updated question description (#794)

Co-authored-by: Rakshit Sinha <rakshit.sinha@oracle.com>

Author: sinharaksh1t

exercises/quiz1.rs

@@ -5,7 +5,7 @@
 
 // Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
 // more than 40 at once, each apple only costs 1! Write a function that calculates
-// the price of an order of apples given the order amount. No hints this time!
+// the price of an order of apples given the quantity bought. No hints this time!
 
 // I AM NOT DONE