pty: deinit should close child end

src/Pty.zig

@@ -80,6 +80,7 @@ pub fn open(size: winsize) !Pty {
 
 pub fn deinit(self: *Pty) void {
     _ = std.os.system.close(self.master);
+    _ = std.os.system.close(self.slave);
     self.* = undefined;
 }
 

src/termio/Exec.zig

@@ -185,9 +185,6 @@ pub fn threadExit(self: *Exec, data: ThreadData) void {
     if (data.ev.process_exited) self.subprocess.externalExit();
     self.subprocess.stop();
 
-    // Wait for our subprocess to report it exited.
-    // data.ev.loop.run(.once);
-
     // Wait for our reader thread to end
     data.read_thread.join();
 }