fix: remove unused Mutex

bindings/javascript/__test__/better-sqlite3.spec.mjs

@@ -32,6 +32,11 @@ test("Property .readonly of database if not set", async (t) => {
   t.is(db.readonly, false);
 });
 
+test("Property .open of database", async (t) => {
+  const db = new Database("foobar.db");
+  t.is(db.open, true);
+});
+
 test("Statement.get() returns data", async (t) => {
   const [db] = await connect(":memory:");
   const stmt = db.prepare("SELECT 1");

bindings/javascript/src/lib.rs

@@ -4,7 +4,7 @@ use std::cell::{RefCell, RefMut};
 use std::num::NonZeroUsize;
 
 use std::rc::Rc;
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 
 use limbo_core::{LimboError, StepResult};
 use napi::iterator::Generator;