fix: correct destruction order comments in Drop TempFile example (#1925)

The comments incorrectly stated that File's drop runs before the custom
drop implementation. In Rust, the custom drop method runs first, and
then fields are dropped afterwards. Updated comments to reflect the
actual destruction order.

Author: Abhinav-ranish

src/trait/drop.md

@@ -76,15 +76,19 @@ impl TempFile {
 }
 
 // When TempFile is dropped:
-// 1. First, our drop implementation will remove the file's name from the filesystem.
-// 2. Then, File's drop will close the file, removing its underlying content from the disk.
+// 1. First, our custom drop implementation runs. The file is still open at this point,
+//    but we can remove it from the filesystem by path.
+// 2. Then, after our drop returns, Rust automatically drops each field,
+//    so File's drop runs and closes the file handle.
 impl Drop for TempFile {
     fn drop(&mut self) {
+        // Note: the File is still open here — field destructors run after this method.
         if let Err(e) = std::fs::remove_file(&self.path) {
             eprintln!("Failed to remove temporary file: {}", e);
         }
         println!("> Dropped temporary file: {:?}", self.path);
-        // File's drop is implicitly called here because it is a field of this struct.
+        // After this method returns, Rust will drop each field (including `file`),
+        // which closes the underlying file handle.
     }
 }