Create a Hello World block plugin

Create a block that displays "Hello World".

Instructions

• Create a new custom module.
  • Create a new directory web/modules/custom/hello_world_block.
  • Create a new file web/modules/custom/hello_world_block/hello_world_block.info.yml
• Create HelloWorldBlock.php file in web/modules/custom/hello_world_block/src/Plugin/Block/
• Set namespace to Drupal/hello_world_block/Plugin/Block
• Create class that extends BlockBase.
  • Set id and admin_label in annotation.
• Implement build() function.