Created consistent money unit

exercises/functions/functions4.rs

@@ -2,7 +2,7 @@
 // Make me compile! Execute `rustlings hint functions4` for hints :)
 
 // This store is having a sale where if the price is an even number, you get
-// 10 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
+// 10 Rustbucks off, but if it's an odd number, it's 3 Rustbucks off.
 
 // I AM NOT DONE
 

exercises/test1.rs

@@ -3,7 +3,7 @@
 // - Variables
 // - Functions
 
-// Mary is buying apples. One apple usually costs 2 dollars, but if you buy
+// 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!