Add more Tracy spans to initialization

src/backend/tty.rs

@@ -269,6 +269,8 @@ impl Tty {
         config: Rc<RefCell<Config>>,
         event_loop: LoopHandle<'static, State>,
     ) -> anyhow::Result<Self> {
+        let _span = tracy_client::span!("Tty::new");
+
         let (session, notifier) = LibSeatSession::new().context(
             "Error creating a session. This might mean that you're trying to run niri on a TTY \
              that is already busy, for example if you're running this inside tmux that had been \
@@ -559,6 +561,8 @@ impl Tty {
             return Ok(());
         }
 
+        let _span = tracy_client::span!("Tty::device_added");
+
         let open_flags = OFlags::RDWR | OFlags::CLOEXEC | OFlags::NOCTTY | OFlags::NONBLOCK;
         let fd = self.session.open(path, open_flags)?;
         let device_fd = DrmDeviceFd::new(DeviceFd::from(fd));