Clean up and unify exercises

exercises/11_hashmaps/hashmaps3.rs

@@ -1,5 +1,3 @@
-// hashmaps3.rs
-//
 // A list of scores (one per line) of a soccer match is given. Each line is of
 // the form : "<team_1_name>,<team_2_name>,<team_1_goals>,<team_2_goals>"
 // Example: England,France,4,2 (England scored 4 goals, France 2).
@@ -11,9 +9,6 @@
 // complete it to pass the test.
 //
 // Make me pass the tests!
-//
-// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a
-// hint.
 
 use std::collections::HashMap;