add spoiler tag + fix attendance additional rewards

lang/en/lang_functions.php

@@ -322,6 +322,8 @@ $lang_functions = array
 	'text_technical_info_help_text' => 'MediaInfo comes from software <b><a href="https://mediaarea.net/en/MediaInfo" target=\'_blank\'>MediaInfo</a></b>，open file, click the view menu > text > right click in the box > select all > copy > past into this box.',
     'text_management_system' => 'Management system',
     'text_seed_points' => 'Seed points',
+    'spoiler_expand_collapse' => 'Click to expand/collapse',
+    'spoiler_default_title' => 'Collapse content',
 );
 
 ?>

lang/en/lang_tags.php

@@ -129,6 +129,10 @@ $lang_tags = array
 	'text_ninety_eight_image_syntax' => " [98img=[auto|number]]image file[/98img]",
 	'text_ninety_eight_image_example' => "[98img=150]uploadfile/2008/10/30/2362924185.png[/98img]",
 	'text_ninety_eight_image_remarks' => "CC98 is a forum at Zhejiang University",
+    'text_spoiler' => 'Spoiler',
+    'text_spoiler_description' => 'Insert expandable/collapsible content on the page',
+    'text_spoiler_syntax' => '[spoiler=title]This is the folded content[/spoiler]',
+    'text_spoiler_example' => '[spoiler=What happened to the final ending of the hero?]The hero died last![/spoiler]',
 );
 
 ?>