Docs: Update the module webpacker migration guide

[ahukkanen]

🎩 What? Why?

This updates the Webpacker migration guide for Decidim modules regarding the new conventions available in the module's assets configuration file (config/assets.rb).

📌 Related Issues

• Related to Configure webpacker additional paths and entry points programmatically #8066, Dynamic stylesheet includes with Webpacker #8115, Fix admin stylesheet dynamic imports #8154

Testing

Read the docs and see if you understand.

📋 Checklist

• ❓ CONSIDER adding a unit test if your PR resolves an issue.
• ✔️ DO check open PR's to avoid duplicates.
• ✔️ DO keep pull requests small so they can be easily reviewed.
• ✔️ DO build locally before pushing.
• ✔️ DO make sure tests pass.
• ✔️ DO make sure any new changes are documented in docs/.
• ✔️ DO add and modify seeds if necessary.
• ✔️ DO add CHANGELOG upgrade notes if required.
• ✔️ DO add to GraphQL API if there are new public fields.
• ✔️ DO add link to MetaDecidim if it's a new feature.
• ❌AVOID breaking the continuous integration build.
• ❌AVOID making significant changes to the overall architecture.

[leio10]

Awesome job!! 😍 👏

[leio10]

I've found that several components are still assigning the stylesheet attribute. I understand that this is not needed anymore, nor the admin_stylesheet attribute, right?
I'm thinking of creating a PR removing those attributes and all the assignments in the component manifests.

[ahukkanen]

Yes, those attributes no longer have any effect.

If you are planning to remove these attributes from the Decidim::ComponentManifest class, I suggest you also create replacement methods for stylesheet=(_ss) and admin_stylesheet=(_ss) that would throw more explanatory errors for the user guiding them to the migration guide.