Fix clippy lint

Author: rsdy

infinitree/src/tree.rs

@@ -352,16 +352,18 @@ impl<I: Index> Infinitree<I> {
         let object = self.object_reader()?;
         let commits_for_field = self.field_for_version(&field.name);
 
-        Ok(<Q as Collection>::Depth::resolve(index, commits_for_field)
-            .map(move |transaction| {
-                QueryIteratorOwned::new(
-                    transaction,
-                    object.clone(),
-                    pred.clone(),
-                    field.strategy.as_mut(),
-                )
-            })
-            .flatten())
+        Ok(
+            <Q as Collection>::Depth::resolve(index, commits_for_field).flat_map(
+                move |transaction| {
+                    QueryIteratorOwned::new(
+                        transaction,
+                        object.clone(),
+                        pred.clone(),
+                        field.strategy.as_mut(),
+                    )
+                },
+            ),
+        )
     }
 
     fn store_start_object(&self, _name: &str) -> ObjectId {