fix(bracket): add bracket to \n

subjects/front-back/README.md

@@ -3,14 +3,14 @@
 ## front-back
 
 - Write a program that prints the previous and next alphabet of a given alphabet.
-    - If the number of arguments is different from `1`, print `"\n"`.
-    - If the length of the argument is different from `1`, print `"\n"`
-    - If the argument is not a letter, print `"\n"`
+    - If the number of arguments is different from `1`, print (`'\n'`).
+    - If the length of the argument is different from `1`, print (`'\n'`)
+    - If the argument is not a letter, print (`'\n'`)
     - Print the previous alphabet and the next alphabet except for the last alphabet of the alphabet.
 
 ### Usage
 
-```shell
+```console
 $ go run . | cat -e 
 $
 $ go run . a | cat -e