adds more generic go offline instructions

src/components/GoOfflineInfo.vue

@@ -3,18 +3,16 @@
     <h2>Please go offline, so your secrets won't leak accidentally</h2>
     <p>
       This application doesn't require Internet access, and you shouldn't be
-      using it from a brower which has one.
+      using it from a browser which has one.
     </p>
     <p>
       It's really trivial to accidentally upload your unencrypted secrets
       somewhere, with a help of your browser spellchecker, webpage translation
       extension and such.
     </p>
-    <p>In Firefox, please go to Menu→More→Work Offline.</p>
     <p>
-      In Chrome, you'll have to open DevTools (Ctrl+Shift+I), then in the
-      Network tab there check the "Offline" checkbox. (DON'T CLOSE DEVELOPER
-      TOOLS AFTER THAT!)
+      Just disable your WiFi in your device settings and unplug any network
+      related cables if applicable.
     </p>
   </div>
 </template>