docs(bevy_state): fix broken links in init_state and insert_state (#13929)

# Objective

Fixes #13845 

## Solution

Fix inline docs links inside `init_state` and `insert_state`. 

## Testing

- Did you test these changes? If so, how?
Manually checked on `cargo doc` and  `rust-analyzer lsp`.

Author: kettei-sproutty

crates/bevy_state/src/app.rs

@@ -18,27 +18,29 @@ pub trait AppExtStates {
     ///
     /// This method is idempotent: it has no effect when called again using the same generic type.
     ///
-    /// Adds [`State<S>`] and [`NextState<S>`] resources, and enables use of the [`OnEnter`], [`OnTransition`] and [`OnExit`] schedules.
-    /// These schedules are triggered before [`Update`](crate::Update) and at startup.
+    /// Adds [`State<S>`] and [`NextState<S>`] resources, and enables use of the [`OnEnter`](crate::state::OnEnter),
+    /// [`OnTransition`](crate::state::OnTransition) and [`OnExit`](crate::state::OnExit) schedules.
+    /// These schedules are triggered before [`Update`](bevy_app::main_schedule::Update) and at startup.
     ///
     /// If you would like to control how other systems run based on the current state, you can
-    /// emulate this behavior using the [`in_state`] [`Condition`].
+    /// emulate this behavior using the [`in_state`](crate::condition::in_state) [`Condition`](bevy_ecs::prelude::Condition).
     ///
     /// Note that you can also apply state transitions at other points in the schedule
-    /// by triggering the [`StateTransition`](`bevy_ecs::schedule::StateTransition`) schedule manually.
+    /// by triggering the [`StateTransition`](struct@StateTransition) schedule manually.
     fn init_state<S: FreelyMutableState + FromWorld>(&mut self) -> &mut Self;
 
     /// Inserts a specific [`State`] to the current [`App`] and overrides any [`State`] previously
     /// added of the same type.
     ///
-    /// Adds [`State<S>`] and [`NextState<S>`] resources, and enables use of the [`OnEnter`], [`OnTransition`] and [`OnExit`] schedules.
-    /// These schedules are triggered before [`Update`](crate::Update) and at startup.
+    /// Adds [`State<S>`] and [`NextState<S>`] resources, and enables use of the [`OnEnter`](crate::state::OnEnter),
+    /// [`OnTransition`](crate::state::OnTransition) and [`OnExit`](crate::state::OnExit) schedules.
+    /// These schedules are triggered before [`Update`](bevy_app::main_schedule::Update) and at startup.
     ///
     /// If you would like to control how other systems run based on the current state, you can
-    /// emulate this behavior using the [`in_state`] [`Condition`].
+    /// emulate this behavior using the [`in_state`](crate::condition::in_state) [`Condition`](bevy_ecs::prelude::Condition).
     ///
     /// Note that you can also apply state transitions at other points in the schedule
-    /// by triggering the [`StateTransition`](`bevy_ecs::schedule::StateTransition`) schedule manually.
+    /// by triggering the [`StateTransition`](struct@StateTransition) schedule manually.
     fn insert_state<S: FreelyMutableState>(&mut self, state: S) -> &mut Self;
 
     /// Sets up a type implementing [`ComputedStates`].