docs(mapper): correct grammar

subjects/mapper/README.md

@@ -2,23 +2,21 @@
 
 ### Instructions
 
-- Create a `map` function that takes an array as first argument, a function as second,
-  and that works like the method .map
+- Create a `map` function that takes an array as the first argument, a function as second, and that works like the method `.map`
 
-- Create a `flatMap` function that takes an array as first argument, a function as second,
-  and that works like the method .flatMap
-
-### Notions
-
-- [devdocs.io/javascript/global_objects/array/map](https://devdocs.io/javascript/global_objects/array/map)
-- [devdocs.io/javascript/global_objects/array/flatmap](https://devdocs.io/javascript/global_objects/array/flatmap)
+- Create a `flatMap` function that takes an array as the first argument, a function as second, and that works like the method `.flatMap`
 
 ### Code provided
 
-> all code provided will be added to your solution and doesn't need to be submited.
+> The provided code will be added to your solution, and does not need to be submitted.
 
 ```js
 Array.prototype.map = undefined
 Array.prototype.flatMap = undefined
 Array.prototype.flat = undefined
 ```
+
+### Notions
+
+- [devdocs.io/javascript/global_objects/array/map](https://devdocs.io/javascript/global_objects/array/map)
+- [devdocs.io/javascript/global_objects/array/flatmap](https://devdocs.io/javascript/global_objects/array/flatmap)