[MOOSE-324] Paragraph Block Class Name

[GeoffDusome]

What does this do/fix?

Note that this was a filter previously introduced & removed from Moose. WP at some point was supporting paragraph blocks having the wp-block-paragraph class, but no longer are, so we need to add this support so some of our related styling can also function as intended.

---

This pull request introduces a new filter to ensure that the core/paragraph block always includes its default CSS class name, improving styling consistency. The implementation uses a reusable trait to add the class name, and registers the new filter in the block definitions.

New Paragraph Block Filter:

• Added a new Paragraph_Filter class that ensures the core/paragraph block always includes its default CSS class by using a shared trait. (wp-content/plugins/core/src/Blocks/Filters/Paragraph_Filter.php)

• Registered the new Paragraph_Filter in the block filters array, so it is applied automatically. (wp-content/plugins/core/src/Blocks/Blocks_Definer.php) [1] [2]

Reusable Trait for Adding Default Class Name:

• Introduced the Add_Block_Default_Class_Name trait, which adds the wp-block-<block name> CSS class to blocks that do not render it by default. This serves as a polyfill until WordPress core provides this functionality. (wp-content/plugins/core/src/Blocks/Filters/Traits/Add_Block_Default_Class_Name.php)

QA

Links to relevant issues

• Link to Issue

[Vinsanity]

🟢

[dpellenwood]

📗 [sigh]