test-js: Use prettier and format all files

Author: https://github.com/mattco98
Commit: 6d58c48c2f
Pull-request: https://github.com/SerenityOS/serenity/pull/2689
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/let-scoping.js

@@ -1,14 +1,14 @@
 test("let scoping", () => {
-    let i = 1;
-    {
-        let i = 3;
-        expect(i).toBe(3);
-    }
-    expect(i).toBe(1);
+  let i = 1;
+  {
+    let i = 3;
+    expect(i).toBe(3);
+  }
+  expect(i).toBe(1);
 
-    {
-        const i = 2;
-        expect(i).toBe(2);
-    }
-    expect(i).toBe(1);
+  {
+    const i = 2;
+    expect(i).toBe(2);
+  }
+  expect(i).toBe(1);
 });