docs(concatalternate): fix subject

- format exercise title
- upgrade instructions
- fix white-spaces and indentation
- add missing import 'piscine'

subjects/concatalernate/README.md

@@ -1,45 +1,47 @@
-## Concat-Alternate
+## concatalternate
-
 
 ### Instructions
 
-Write a function that receives two slices of int as arguments and returns a new one with the result of alternating the values of each.
+Write a function `ConcatAlternate()` that receives two slices of an `int` as arguments and returns a new slice with the result of the alternated values of each slice.
-- The input slices may be of different lengths.
+- The input slices can be of different lengths.
-- The new slice should contain the elements of the larger slice first and then the elements of the smaller slice.
+- The new slice should return the elements of the larger slice first and then the elements of the smaller slice.
-- If the slices are of equal length, the new slice should contain the elements of the first slice first and then the elements of the second slice.
+- If the slices are of equal length, the new slice should return the elements of the first slice first and then the elements of the second slice.
 - The new slice should be in the same order as the input slices.
 
 ### Expected function
 
 ```go
 func ConcatAlternate(slice1,slice2 []int) []int {
-    
+
 }
 ```
 
 ### Usage
 
-Here is a possible program to test your function :
+Here is a possible program to test your function:
 
 ```go
 package main
 
 import (
 	"fmt"
+	"piscine"
 )
 
 func main() {
-	fmt.Println(ConcatAlternate([]int{1,2,3},[]int{4,5,6}))
+	fmt.Println(piscine.ConcatAlternate([]int{1, 2, 3}, []int{4, 5, 6}))
-	fmt.Println(ConcatAlternate([]int{1,2,3},[]int{4,5,6,7,8,9}))
+	fmt.Println(piscine.ConcatAlternate([]int{1, 3, 5, 7, 9}, []int{2, 4, 6, 8, 10}))
-	fmt.Println(ConcatAlternate([]int{1,2,3},[]int{}))
+	fmt.Println(piscine.ConcatAlternate([]int{1, 2, 3}, []int{4, 5, 6, 7, 8, 9}))
+	fmt.Println(piscine.ConcatAlternate([]int{1, 2, 3}, []int{}))
 }
 ```
 
-And its output :
+And its output:
 
 ```console
 $ go run .
-[1, 4, 2, 5, 3, 6]
+[1 4 2 5 3 6]
-[1, 4, 2, 5, 3, 6, 7, 8, 9]
+[1 2 3 4 5 6 7 8 9 10]
-[1, 2, 3]
+[4 1 5 2 6 3 7 8 9]
+[1 2 3]
 ```