lock vault shortcut only for safari (#1452)

src/content/shortcuts.ts

@@ -29,16 +29,16 @@ document.addEventListener('DOMContentLoaded', (event) => {
         Mousetrap.bind('mod+shift+y', () => {
             sendMessage('open_popup');
         });
+
+        Mousetrap.bind('mod+shift+s', () => {
+            sendMessage('lock_vault');
+        });
     } else {
         Mousetrap.bind('mod+shift+9', () => {
             sendMessage('generate_password');
         });
     }
 
-    Mousetrap.bind('mod+shift+s', () => {
-        sendMessage('lock_vault');
-    });
-
     function sendMessage(shortcut: string) {
         const msg: any = {
             command: 'keyboardShortcutTriggered',