Clean up unnecessary use of RefCell

src/main.rs

@@ -134,7 +134,7 @@ fn main() {
         .expect("failed to get initial audio devices and sessions");
 
     let (tx, rx): (Sender<String>, Receiver<String>) = mpsc::channel();
-    *WIN_CHANGE_CHANNEL_TX.lock().unwrap().borrow_mut() = Some(tx);
+    *WIN_CHANGE_CHANNEL_TX.lock().unwrap() = Some(tx);
 
     thread::spawn(move || {
         win_event_hook_loop();

src/window_change.rs

@@ -1,5 +1,4 @@
 use std::{
-    cell::RefCell,
     sync::{mpsc::Sender, Mutex},
 };
 
@@ -18,7 +17,7 @@ use windows::Win32::{
 
 use crate::pid_to_exe::pid_to_exe_path;
 
-pub static WIN_CHANGE_CHANNEL_TX: Mutex<RefCell<Option<Sender<String>>>> = Mutex::new(RefCell::new(None));
+pub static WIN_CHANGE_CHANNEL_TX: Mutex<Option<Sender<String>>> = Mutex::new(None);
 
 unsafe extern "system" fn win_event_proc(
     _hook: HWINEVENTHOOK,
@@ -40,7 +39,6 @@ unsafe extern "system" fn win_event_proc(
                 WIN_CHANGE_CHANNEL_TX
                     .lock()
                     .unwrap()
-                    .borrow()
                     .as_ref()
                     .unwrap()
                     .send(path)