update loaing

lib/core/providers/QUICK_REFERENCE.md

@@ -31,7 +31,7 @@ Future<User> user(UserRef ref, String id) async {
 final userAsync = ref.watch(userProvider('123'));
 userAsync.when(
   data: (user) => Text(user.name),
-  loading: () => CircularProgressIndicator(),
+  loading: () => const CustomLoadingIndicator(),
   error: (e, _) => Text('Error: $e'),
 );
 ```
@@ -202,7 +202,7 @@ final newValue = ref.refresh(userProvider);
 ```dart
 asyncValue.when(
   data: (value) => Text(value),
-  loading: () => CircularProgressIndicator(),
+  loading: () => const CustomLoadingIndicator(),
   error: (error, stack) => Text('Error: $error'),
 );
 ```
@@ -215,7 +215,7 @@ switch (asyncValue) {
   case AsyncError(:final error):
     return Text('Error: $error');
   case AsyncLoading():
-    return CircularProgressIndicator();
+    return const CustomLoadingIndicator();
 }
 ```