Blocks: Introduce the block parser.
The WP_Block_Parser
class, and the accompanying parse_blocks()
helper function, can be used to parse an array of blocks out of a content string.
WP_Block_Parser
is copied from the @wordpress/block-serialization-default-parser
package. To ensure it stays in sync with the JavaScript parser, changes should be implemented in the package first, then the package version should be upgraded to include the changes.
See #45109.