docs: add comment explaining Strapi 5 publishedAt behavior

Added clarifying comment that publishedAt is always set in Strapi 5
even when draftAndPublish is disabled, with link to migration docs.

Author: hoangvietfreelancer

server/src/services/meilisearch/config.js

@@ -237,6 +237,8 @@ export default ({ strapi }) => {
       if (entriesQuery.status === 'draft') {
         return entries
       } else {
+        // In strapi 5, publishedAt is always set even draftAndPublish is disabled
+        // More information: https://docs.strapi.io/cms/migration/v4-to-v5/breaking-changes/publishedat-always-set-when-dandp-disabled
         return entries.filter(
           entry =>
             !(entry?.publishedAt === undefined || entry?.publishedAt === null),