chore: tweak how-to layout

Author: tianzhou

content/reference/mysql/how-to/_layout.md

@@ -3,10 +3,10 @@
 
 ## [Overview](/reference/mysql/how-to/overview)
 
+## [How to enable slow query log](/reference/mysql/how-to/how-to-enable-slow-query-log-mysql)
+
 ## [How to CREATE INDEX](/reference/mysql/how-to/how-to-create-index-mysql)
 
 ## [How to ALTER TABLE](/reference/mysql/how-to/how-to-alter-table-mysql)
 
 ## [How to CREATE TABLE](/reference/mysql/how-to/how-to-create-table-mysql)
-
-## [How to enable slow query log](/reference/mysql/how-to/how-to-enable-slow-query-log-mysql)