docs: implement Miguel's feedback

subjects/card_deck/README.md

@@ -7,7 +7,7 @@ Represent the cards from a deck:
 
 - Create an `enum` to represent the `Suit`.
 - Implement the associated **function** `random`, which returns a random `Suit` (`Heart`, `Diamond`, `Spade` or `Club`).
-- Create a `Rank` enum. For ace and face cards, it can be one of `Ace`, `King`, `Queen` or `Jack`. For  for the values from 2 to 10, it can have a `Number` value associated to a `u8`.
+- Create a `Rank` enum. For ace and face cards, it can be one of `Ace`, `King`, `Queen` or `Jack`. For the values from 2 to 10, it can have a `Number` value associated to a `u8`.
 - Create an associated **function** to `Rank` called `Random` that returns a random `Rank`.
 - Create a structure name `Card` which has the fields `suit` and `rank`.
 

subjects/changes/README.md

@@ -4,7 +4,7 @@
 
 Imagine you are working on some software to control smart lights in a house. You have access to an array of all the lights in that house.
 
-Define the associated **function** `new`, and add it to the data structure `Light`. It should create a new light with the alias passed as an argument, with a brightness of .
+Define the associated **function** `new`, and add it to the data structure `Light`. It should create a new light with the alias passed as an argument, with a brightness of 0.
 
 Define the **function** `change_brightness`, which receives a `Vec` of lights, an `alias` and a `u8`value. It should find the light in the `Vec` by its alias, and set the value of the brightness.