[Docs] Update upgrade docs

docs/prerequisites.md

@@ -51,3 +51,8 @@ Thus in your AppServiceProvider you will need to set `Schema::defaultStringLengt
 
 This package expects the primary key of your `User` model to be an auto-incrementing `int`. If it is not, you may need to modify the `create_permission_tables` migration and/or modify the default configuration. See [https://spatie.be/docs/laravel-permission/advanced-usage/uuid](https://spatie.be/docs/laravel-permission/advanced-usage/uuid) for more information. 
 
+## Database foreign-key relationship support
+
+To enforce database integrity, this package uses foreign-key relationships with cascading deletes. This prevents data mismatch situations if database records are manipulated outside of this package. If your database engine does not support foreign-key relationships, then you will have to alter the migration files accordingly.
+
+IMPROVEMENTS TO FOREIGN KEY HANDLING WERE ADDED IN v6, SO UPGRADING IS RECOMMENDED.

docs/upgrading.md

@@ -7,19 +7,21 @@ weight: 6
 
 ALL upgrades of this package should follow these steps:
 
-1. Upgrading between major versions of this package always require the usual Composer steps:
+1. Composer. Upgrading between major versions of this package always require the usual Composer steps:
    - Update your `composer.json` to specify the new major version, such as `^6.0`
    - Then run `composer update`. 
 
-2. Compare the `migration` file stubs in the NEW version of this package against the migrations you've already run inside your app. If necessary, create a new migration (by hand) to apply any new changes.
+2. Migrations. Compare the `migration` file stubs in the NEW version of this package against the migrations you've already run inside your app. If necessary, create a new migration (by hand) to apply any new database changes.
 
-3. If you have made any custom Models from this package into your own app, compare the old and new models and apply any relevant updates to your custom models.
+3. Config file. Incorporate any changes to the permission.php config file, updating your existing file. (It may be easiest to make a backup copy of your existing file, re-publish it from this package, and then re-make your customizations to it.)
 
-4. If you have overridden any methods from this package's Traits, compare the old and new traits, and apply any relevant updates to your overridden methods.
+4. Models. If you have made any custom Models from this package into your own app, compare the old and new models and apply any relevant updates to your custom models.
 
-5. Apply any version-specific special updates as outlined below...
+5. Custom Methods/Traits. If you have overridden any methods from this package's Traits, compare the old and new traits, and apply any relevant updates to your overridden methods.
 
-6. Review the changelog, which details all the changes: https://github.com/spatie/laravel-permission/blob/main/CHANGELOG.md
+6. Apply any version-specific special updates as outlined below...
+
+7. Review the changelog, which details all the changes: [CHANGELOG](https://github.com/spatie/laravel-permission/blob/main/CHANGELOG.md)
 and/or consult the [Release Notes](https://github.com/spatie/laravel-permission/releases)