fix: make expected results more descriptive for numbers/circle-area exercise

08-numbers-and-strings/01-numbers/exercises/07-circle-area/main.go

@@ -24,12 +24,16 @@ import (
 //  For PI you can use `math.Pi`
 //
 // EXPECTED OUTPUT
-//  314.1592653589793
+//  go run main.go 10
+//    radius: 10 -> area: 314.1592653589793
 //
 // BONUS EXERCISE!
 //   1. Print the area as 314.16
 //   2. To do that you need to use the correct Printf verb :)
 //      Instead of `%g` verb below.
+//
+//   go run main.go 10
+//     radius: 10 -> area: 314.16
 // ---------------------------------------------------------
 
 func main() {