Editor: Extend register_block_type to accept the path file or folder with block.json

Rather than using two distinct methods to register block types in WordPress core, let's make `register_block_type` the canonical method to deal with all use cases. In practice, the patch proposed extends its usage to work as a proxy to `register_block_type_from_metadata`. It should remove some confusion that we observed and let us be more explicit what's the latest recommendation.

Props matveb, mcsf.
Fixes #53233.



git-svn-id: https://develop.svn.wordpress.org/trunk@50927 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/blocks/register.php

@@ -382,6 +382,18 @@ class WP_Test_Block_Register extends WP_UnitTestCase {
 		);
 	}
 
+	/**
+	 * @ticket 53233
+	 */
+	function test_block_register_block_type_proxy_for_metadata() {
+		$result = register_block_type(
+			DIR_TESTDATA . '/blocks/notice'
+		);
+
+		$this->assertInstanceOf( 'WP_Block_Type', $result );
+		$this->assertSame( 'tests/notice', $result->name );
+	}
+
 	/**
 	 * @ticket 52301
 	 */