1413-shopping_mall-subject fix: functions names

3 functions didn't match the name in the tests

subjects/shopping_mall/README.md

@@ -5,10 +5,10 @@
 Using the `mall` module provided, create the following **functions** to help run a shopping mall:
 
 - `biggest_store`: receives a `Mall` and returns the `Store` with the biggest `square_meters`.
-- `highest_paid_employees`: receives a `Mall` and returns a vector containing the `Employee`(s) with the highest salary.
+- `highest_paid_employee`: receives a `Mall` and returns a vector containing the `Employee`(s) with the highest salary.
 - `nbr_of_employees`: receives a `Mall` and returns the number of employees and guards as a `usize`.
-- `fire_old_guards`: receives a `Mall` and removes from the `Mall.guards` all guards who are 50 years old or over.
-- `check_for_guards`: receives a `Mall` and a vector of `Guard`. If there is not at least 1 guard for every 200 square meters of floor size, a guard should be added to the `Mall.guards`.
+- `fire_old_securities`: receives a `Mall` and removes from the `Mall.guards` all guards who are 50 years old or over.
+- `check_for_securities`: receives a `Mall` and a vector of `Guard`. If there is not at least 1 guard for every 200 square meters of floor size, a guard should be added to the `Mall.guards`.
 - `cut_or_raise`: receives a `Mall`. For each employee, the salary will be raised by 10% if they work more than 10 hours, else their salary will be decreased by 10%. You can consider that guards are not employees of the mall.
 
 ### Expected Function