make ls -lf outputs full path in symbolic target (#13605)

# Description
Fixes: #13479 

# User-Facing Changes
Given the following setup:
```
cd /tmp
touch src_file.txt
ln -s src_file.txt link1
```
### Before 
```
ls -lf link1 | get target.0  # It outputs src_file.txt
```
### After
```
ls -lf link1 | get target.0  # It outputs /tmp/src_file.txt
```
# Tests + Formatting
Added a test for the change

crates/nu-command/src/filesystem/ls.rs

@@ -5,7 +5,7 @@ use nu_engine::glob_from;
 #[allow(deprecated)]
 use nu_engine::{command_prelude::*, env::current_dir};
 use nu_glob::MatchOptions;
-use nu_path::expand_to_real_path;
+use nu_path::{expand_path_with, expand_to_real_path};
 use nu_protocol::{DataSource, NuGlob, PipelineMetadata, Signals};
 use pathdiff::diff_paths;
 
@@ -412,6 +412,7 @@ fn ls_for_one_pattern(
                         du,
                         &signals,
                         use_mime_type,
+                        args.full_paths,
                     );
                     match entry {
                         Ok(value) => Some(value),
@@ -522,6 +523,7 @@ pub(crate) fn dir_entry_dict(
     du: bool,
     signals: &Signals,
     use_mime_type: bool,
+    full_symlink_target: bool,
 ) -> Result<Value, ShellError> {
     #[cfg(windows)]
     if metadata.is_none() {
@@ -551,7 +553,23 @@ pub(crate) fn dir_entry_dict(
                 "target",
                 if md.file_type().is_symlink() {
                     if let Ok(path_to_link) = filename.read_link() {
-                        Value::string(path_to_link.to_string_lossy(), span)
+                        // Actually `filename` should always have a parent because it's a symlink.
+                        // But for safety, we check `filename.parent().is_some()` first.
+                        if full_symlink_target && filename.parent().is_some() {
+                            Value::string(
+                                expand_path_with(
+                                    path_to_link,
+                                    filename
+                                        .parent()
+                                        .expect("already check the filename have a parent"),
+                                    true,
+                                )
+                                .to_string_lossy(),
+                                span,
+                            )
+                        } else {
+                            Value::string(path_to_link.to_string_lossy(), span)
+                        }
                     } else {
                         Value::string("Could not obtain target file's path", span)
                     }

crates/nu-command/tests/commands/ls.rs

@@ -808,3 +808,28 @@ fn list_inside_tilde_glob_metachars_dir() {
         },
     );
 }
+
+#[test]
+fn list_symlink_with_full_path() {
+    Playground::setup("list_symlink_with_full_path", |dirs, sandbox| {
+        sandbox.with_files(&[EmptyFile("test_file.txt")]);
+
+        #[cfg(unix)]
+        let _ = std::os::unix::fs::symlink("test_file.txt", dirs.test().join("test_link1"));
+        #[cfg(windows)]
+        let _ = std::os::windows::fs::symlink_file("test_file.txt", dirs.test().join("test_link1"));
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls -l test_link1 | get target.0"
+        );
+        assert_eq!(actual.out, "test_file.txt");
+        let actual = nu!(
+            cwd: dirs.test(),
+            "ls -lf test_link1 | get target.0"
+        );
+        assert_eq!(
+            actual.out,
+            dirs.test().join("test_file.txt").to_string_lossy()
+        );
+    })
+}