Added docs about MinimalPlugins looping as fast as possible. (#17241)

This also includes suggestions and an example on how to limit the loop
speed.
Fixes #17147.

---------

Co-authored-by: François Mockers <[email protected]>

crates/bevy_internal/src/default_plugins.rs

@@ -119,4 +119,17 @@ plugin_group! {
     /// It includes a [schedule runner (`ScheduleRunnerPlugin`)](crate::app::ScheduleRunnerPlugin)
     /// to provide functionality that would otherwise be driven by a windowed application's
     /// *event loop* or *message loop*.
+    ///
+    /// By default, this loop will run as fast as possible, which can result in high CPU usage.
+    /// You can add a delay using [`run_loop`](crate::app::ScheduleRunnerPlugin::run_loop),
+    /// or remove the loop using [`run_once`](crate::app::ScheduleRunnerPlugin::run_once).
+    /// # Example:
+    /// ```rust, no_run
+    /// # use std::time::Duration;
+    /// # use bevy_app::{App, PluginGroup, ScheduleRunnerPlugin};
+    /// # use bevy_internal::MinimalPlugins;
+    /// App::new().add_plugins(MinimalPlugins.set(ScheduleRunnerPlugin::run_loop(
+    ///     // Run 60 times per second.
+    ///     Duration::from_secs_f64(1.0 / 60.0),
+    /// ))).run();
 }