fix lang attr in official website

Author: lovasoa

examples/official-site/index.sql

@@ -4,7 +4,7 @@ select 'shell' as component,
     'SQLPage' as title,
     'database' as icon,
     '/' as link,
-    'en-US' as lang,
+    'en-US' as language,
     'Official SQLPage website: write web applications in SQL !' as description,
     'get started' as menu_item,
     'documentation' as menu_item,

examples/official-site/sqlpage/migrations/01_documentation.sql

@@ -442,7 +442,7 @@ INSERT INTO example(component, description, properties) VALUES
             "title": "SQLPage documentation",
             "link": "/",
             "menu_item": "index",
-            "lang": "en-US",
+            "language": "en-US",
             "description": "Documentation for the SQLPage low-code web application framework.",
             "font": "Poppins",
             "icon": "book",

examples/official-site/your-first-sql-website/index.sql

@@ -5,7 +5,7 @@ select 'shell' as component,
     'Your SQL Website' as title,
     'database' as icon,
     '/' as link,
-    'en-US' as lang,
+    'en-US' as language,
     'Get started with SQLPage: short tutorial for making a SQL-only website' as description,
     'documentation' as menu_item,
     20 as font_size,