Changeset 43742 for branches/5.0/src/wp-includes/class-wp-block-type-registry.php

Blocks: Introduce WP_Block_Type and WP_Block_Type_Registry classes.

These are the foundational classes allowing blocks to be registered and used throughout WordPress.

This commit also includes the has_block() and has_blocks() functions, which are required for unit testing these classes.

Props adamsilverstein, danielbachhuber, desrosj.
See #45097, #45109.