Update _index.md

Updated Getting Started docs to match the change at bevyengine/bevy#6247 and replace from_seconds(time, bool) with from_seconds(time, TimerMode)

content/learn/book/getting-started/resources/_index.md

@@ -50,12 +50,11 @@ fn greet_people(
 }
 ```
 
-Now all that's left is adding a `GreetTimer` Resource to our `HelloPlugin`:
+Now all that's left is adding a `GreetTimer` Resource to our `HelloPlugin`. Use `TimerMode::Repeating` to make the timer repeat.
 ```rs
 impl Plugin for HelloPlugin {
     fn build(&self, app: &mut App) {
-        // the reason we call from_seconds with the true flag is to make the timer repeat itself
-        app.insert_resource(GreetTimer(Timer::from_seconds(2.0, true)))
+        app.insert_resource(GreetTimer(Timer::from_seconds(2.0, TimerMode::Repeating)))
             .add_startup_system(add_people)
             .add_system(greet_people);
     }