refactoring: use chrono format function to format date

src/builtins/ls.rs

@@ -1,6 +1,6 @@
 use std::{fs::metadata, path::PathBuf, str::FromStr};
 
-use chrono::{DateTime, Datelike, Local, Timelike};
+use chrono::{DateTime, Datelike, Local};
 
 use crate::error::ShellError;
 
@@ -69,14 +69,9 @@ fn format_filesize(filesize: u64) -> String {
 fn format_date(date: DateTime<Local>) -> String {
     let now: DateTime<Local> = Local::now();
     if date.day() != now.day() || date.month() != now.month() || date.year() != now.year() {
-        format!("{}-{:02}-{:02}", date.year(), date.month(), date.day())
+        date.format("%F").to_string()
     } else {
-        format!(
-            "{:02}:{:02}:{:02}",
-            date.hour(),
-            date.minute(),
-            date.second()
-        )
+        date.format("%T").to_string()
     }
 }