Updates secrets for order of operations clarity (#1536)

* Updates instruction for order of operations

The order matters and is clear

* Format

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Co-authored-by: Angelika Cathor <angelikacathor@fastmail.com>

exercises/concept/secrets/.docs/instructions.md

@@ -73,10 +73,10 @@ xorer.(3)
 Implement `Secrets.secret_combine/2`. It should return a function which takes one argument and applies to it the two functions passed in to `secret_combine` in order.
 
 ```elixir
-multiply = Secrets.secret_multiply(7)
-divide = Secrets.secret_divide(3)
-combined = Secrets.secret_combine(multiply, divide)
+add_one = Secrets.secret_add(1)
+multiply_by_2 = Secrets.secret_multiply(2)
+combined = Secrets.secret_combine(add_one, multiply_by_2)
 
-combined.(6)
-# => 14
+combined.(3)
+# => 8
 ```