[FormData] 번역 - line52(#1232)

Author: Bangseungjae

5-network/02-formdata/article.md

@@ -49,7 +49,7 @@ Let's send a simple form first.
 
 In this example, the server code is not presented, as it's beyound our scope. The server accepts the POST request and replies "User saved".
 
-## FormData Methods
+## FormData 메서드
 
 We can modify fields in `FormData` with methods: