Fix excess capacity reservation in Graph::with_capacity

The passed node count should only be used to reserve space in collections that
will have an entry for all or most nodes. That doesn't include the list of
input, output and capture node IDs.

src/graph.rs

@@ -727,9 +727,9 @@ impl Graph {
             nodes: Vec::with_capacity(n_nodes),
             cached_plan: Mutex::new(None),
             source_ids: FxHashMap::default(),
-            input_ids: Vec::with_capacity(n_nodes),
-            output_ids: Vec::with_capacity(n_nodes),
-            captures: Vec::with_capacity(n_nodes),
+            input_ids: Vec::new(),
+            output_ids: Vec::new(),
+            captures: Vec::new(),
             node_id_from_name: HashMap::with_capacity(n_nodes),
         }
     }