📝 Provide a description of the new feature

This is a followup for another issue: #18804

In #18750, we have added a validator that prevents the introduction of regression related to this issue - #18583.

We agreed to export a plugin class as a value instead of a type.

Unfortunately, we do not have any rule that forces it.

Definition of Done

Let's use the following file as an example:

After applying the following change:

diff --git a/packages/ckeditor5-basic-styles/src/index.ts b/packages/ckeditor5-basic-styles/src/index.ts
index 5cf0a7bcbf..f3dd063082 100644
--- a/packages/ckeditor5-basic-styles/src/index.ts
+++ b/packages/ckeditor5-basic-styles/src/index.ts
@@ -7,7 +7,7 @@
  * @module basic-styles
  */
 
-export { Bold } from './bold.js';
+export type { Bold } from './bold.js';
 export { BoldEditing } from './bold/boldediting.js';
 export { BoldUI } from './bold/boldui.js';
 export { Code } from './code.js';

And executing: node scripts/ci/validate-module-re-exports.mjs, I would expect an error. In the current implementation it does not list it as an error.