trash: Use non-existing name when restoring image

We usually use the original path of the image.
For the rare case the original file name exists we create
one that is not used yet.

Closes #66

Part-of: <https://gitlab.gnome.org/Incubator/loupe/-/merge_requests/130>

src/window.rs

@@ -533,7 +533,7 @@ impl LpWindow {
 
     /// Permanently delete image
     ///
-    /// Fallback for when trash no available
+    /// Fallback for when trash not available
     async fn delete(&self, path: &Path) {
         let dialog = adw::MessageDialog::builder()
             .modal(true)