fix(if1): Remove `return` reference

This closes #153.

Cargo.lock

@@ -600,7 +600,7 @@ dependencies = [
 
 [[package]]
 name = "rustlings"
-version = "1.4.1"
+version = "1.5.0"
 dependencies = [
  "assert_cmd 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",

exercises/if/if1.rs

@@ -3,7 +3,6 @@
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
-    // - return
     // - another function call
     // - additional variables
     // Scroll down for hints.