fix: correct import path for catalogPermissionRules.ts

Update incorrect file path reference in catalogPermissionRules.ts import statement.

Signed-off-by: chonpisitkong01 <112919164+chonpisitkong01@users.noreply.github.com>

docs/permissions/custom-rules.md

@@ -184,7 +184,7 @@ To install custom rules in a plugin, we need to use the [`PermissionsRegistrySer
      import('@backstage/plugin-catalog-backend-module-scaffolder-entity-model'),
    );
    /* highlight-add-next-line */
-   backend.add(import('./extensions/catalogPermissionRules'));
+   backend.add(import('./modules/catalogPermissionRules.ts'));
    ```
 
 5. Now when you run you Backstage instance - `yarn start` - the rule will be added to the catalog plugin.