fix(byebyefirst): fix folder

- moved README.md to correct directory
- fixed grammar and added test cases

byebyefirst/README.md

@@ -1,35 +0,0 @@
-## byebyefirst
-
-### Instructions
-
-Write a function that takes a slice of strings and returns a new slice without the first element. If the slice is empty, return the empty slice.
-
-### Expected function
-
-```go
-func ByeByeFirst(strings []string) []string {
-}
-```
-
-### Usage
-
-Here is a possible program to test your function :
-
-```go
-package main
-
-func main() {
-	fmt.Println(ByeByeFirst([]string{}))
-	fmt.Println(ByeByeFirst([]string{"first", "second"}))
-	fmt.Println(ByeByeFirst([]string{"", "abcd", "efg"}))
-}
-```
-
-And its output :
-
-```console
-$ go run . | cat -e
-[]$
-[second]$
-[abcd efg]$
-```

subjects/byebyefirst/README.md

@@ -0,0 +1,46 @@
+## byebyefirst
+
+### Instructions
+
+Write a function that takes a slice of `string` and returns a new slice without the first element. 
+
+- If the slice is empty, return the empty slice.
+
+### Expected function
+
+```go
+func ByeByeFirst(strings []string) []string {
+
+}
+```
+
+### Usage
+
+Here is a possible program to test your function:
+
+```go
+package main
+
+import (
+	"fmt"
+
+	"piscine"
+)
+
+func main() {
+	fmt.Println(piscine.ByeByeFirst([]string{}))
+	fmt.Println(piscine.ByeByeFirst([]string{"one arg"}))
+	fmt.Println(piscine.ByeByeFirst([]string{"first", "second"}))
+	fmt.Println(piscine.ByeByeFirst([]string{"", "abcd", "efg"}))
+}
+```
+
+And its output:
+
+```console
+$ go run . | cat -e
+[]$
+[]$
+[second]$
+[abcd efg]$
+```