Clean up and unify exercises

exercises/03_if/if2.rs

@@ -1,9 +1,5 @@
-// if2.rs
-//
 // Step 1: Make me compile!
 // Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
-//
-// Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
 
 pub fn foo_if_fizz(fizzish: &str) -> &str {
     if fizzish == "fizz" {