Fix file watching for symlinks (#17609)

Closes #17605

Watches for target paths if file watched is a symlink in Linux. 
This will check if the generated `notify::Event` has any paths matching
the `root_path` and if the file is a symlink it will also check if the
path matches the `target_root_path` (the path that the symlink is
pointing to)

Release Notes:

- Added file watching for symlinks

crates/fs/src/fs.rs

@@ -587,7 +587,12 @@ impl Fs for RealFs {
         let pending_paths: Arc<Mutex<Vec<PathEvent>>> = Default::default();
         let root_path = path.to_path_buf();
 
-        watcher::global(|g| {
+        // Check if root path is a symlink
+        let target_path = self.read_link(&path).await.ok();
+
+        watcher::global({
+            let target_path = target_path.clone();
+            |g| {
                 let tx = tx.clone();
                 let pending_paths = pending_paths.clone();
                 g.add(move |event: &notify::Event| {
@@ -601,10 +606,20 @@ impl Fs for RealFs {
                         .paths
                         .iter()
                         .filter_map(|path| {
-                        path.starts_with(&root_path).then(|| PathEvent {
+                            if let Some(target) = target_path.clone() {
+                                if path.starts_with(target) {
+                                    return Some(PathEvent {
                                         path: path.clone(),
                                         kind,
-                        })
+                                    });
+                                }
+                            } else if path.starts_with(&root_path) {
+                                return Some(PathEvent {
+                                    path: path.clone(),
+                                    kind,
+                                });
+                            }
+                            None
                         })
                         .collect::<Vec<_>>();
 
@@ -619,6 +634,7 @@ impl Fs for RealFs {
                         });
                     }
                 })
+            }
         })
         .log_err();
 
@@ -626,6 +642,14 @@ impl Fs for RealFs {
 
         watcher.add(path).ok(); // Ignore "file doesn't exist error" and rely on parent watcher.
 
+        // Check if path is a symlink and follow the target parent
+        if let Some(target) = target_path {
+            watcher.add(&target).ok();
+            if let Some(parent) = target.parent() {
+                watcher.add(parent).log_err();
+            }
+        }
+
         // watch the parent dir so we can tell when settings.json is created
         if let Some(parent) = path.parent() {
             watcher.add(parent).log_err();