Update 12-keywords.md

docs/en/12-taos-sql/12-keywords.md

@@ -4,7 +4,7 @@ title: Keywords
 
 There are about 200 keywords reserved by TDengine, they can't be used as the name of database, STable or table with either upper case, lower case or mixed case.
 
-**Keywords List**
+## Keyword List
 
 ### A