Intended to simplify the lesson by removing the need to figure out what the value is meant to be based on the tests. Previous commits (https://github.com/rust-lang/rustlings/commit/9ca08b8f2b09366e97896a4a8cf9ff3bb4d54380 and https://github.com/rust-lang/rustlings/commit/114b54cbdb977234b39e5f180d937c14c78bb8b2#diff-ce1c232ff0ddaff909351bb84cb5bff423b5b9e04f21fd4db7ffe443e598e174) removed the mathematical complexity, and I feel this addition is a needed change to further streamline the exercise.
Structs
Rust has three struct types: a classic C struct, a tuple struct, and a unit struct.