Translation needed for existing languages

@sumn2u has made changes on the original english version of the book (PR #221)

Visual Diff of Changes:

diff --git a/en/functions/closures.md b/en/functions/closures.md
index acd1fd6..8cc3b6a 100644
--- a/en/functions/closures.md
+++ b/en/functions/closures.md
@@ -3,8 +3,6 @@ chapter: 8
 description: Closures are a JavaScript concept that allows functions to access and remember variables from their containing scope, even after the outer function has finished running. They're vital for data encapsulation, private variables, and various design patterns in JavaScript. Closures enhance code flexibility and maintainability.
 ---
 
----
-
 # Closures
 
 In JavaScript, closures are a fundamental and powerful concept that plays a crucial role in the language. Understanding closures is essential for writing clean, efficient, and maintainable code. In this chapter, we'll explore what closures are, how they work, and why they are important in JavaScript.

Review PR #221 and the referenced en/functions/closures.md change to understand the source content. Identify which existing language translations are intended, then update the corresponding translated book files and verify that they reflect the current English version.