simplifying list generation for mime types, applying xdg-mime patch & cargo fmt

src/mime_icon.rs

@@ -78,4 +78,4 @@ pub fn parent_mime_types(mime: &Mime) -> Option<Vec<Mime>> {
     let mut mime_icon_cache = MIME_ICON_CACHE.lock().unwrap();
 
     mime_icon_cache.shared_mime_info.get_parents_aliased(mime)
-}
+}