Re-add syntax highlighting to daily emails and

...ATDC lessons

source/_daily_emails/2023-04-19.md

@@ -17,7 +17,7 @@ Why? I didn't like the inconsistency of using one approach for variable names an
 
 I'd have had code like this with a mixture of both:
 
-```php
+```language-php
 class MyClass {
 
   private EntityTypeManagerInterface $entityTypeManager;
@@ -31,7 +31,7 @@ class MyClass {
 
 Or even more simply:
 
-```php
+```language-php
 $entity_type_manager = \Drupal::entityTypeManager();
 ```