Remove references to CoreStage in docs

src/frame_counting.rs

@@ -5,7 +5,7 @@ use serde::{Deserialize, Serialize};
 use std::ops::{Add, Sub};
 /// The number of frames that have elapsed since the app started
 ///
-/// Updated in [`time_tracker`] during [`CoreStage::First`].
+/// Updated in [`time_tracker`] during the [`First`] schedule.
 #[derive(
     Resource,
     Clone,
@@ -38,7 +38,7 @@ impl Sub<FrameCount> for FrameCount {
 
 /// A system which increases the value of the [`FrameCount`] resource by 1 every frame
 ///
-/// This system should run during [`CoreStage::First`].
+/// This system should run during the [`First`] schedule.
 pub fn frame_counter(mut frame_count: ResMut<FrameCount>) {
     frame_count.0 += 1;
 }

src/input_playback.rs

@@ -22,7 +22,7 @@ use crate::timestamped_input::{TimestampedInputEvent, TimestampedInputs};
 
 /// Reads from the [`TimestampedInputs`] event stream to determine which events to play back.
 ///
-/// Events are played back during [`CoreStage::First`] to accurately mimic the behavior of native `winit`-based inputs.
+/// Events are played back during the [`First`] schedule to accurately mimic the behavior of native `winit`-based inputs.
 /// Which events are played back are controlled via the [`PlaybackStrategy`] resource.
 ///  
 /// Input is deserialized on app startup from the path stored in the [`PlaybackFilePath`] resource, if any.