[feature/template-events] Add additional space for editors

Use `' ?'. '>'` rather than `' ?>'` as the latter causes problems
in some editors.

PHPBB3-9550

phpBB/includes/template/filter.php

@@ -914,7 +914,7 @@ class phpbb_template_filter extends php_user_filter
 			}
 			// Need spaces inside php tags as php cannot grok
 			// < ?php? > sans the spaces
-			return ' ?>' . $all_compiled . '<?php ';
+			return ' ?' . '>' . $all_compiled . '<?php ';
 		}
 
 		// 1. find all mods defining hooks for location