Add DIRECTION,LENGTH and LANGUAGE as allowed keyword (#3801)

Author: MasterKuat

sql/snowflake/SnowflakeParser.g4

@@ -3551,6 +3551,9 @@ keyword
     | COMMENT
     | ORDER
     | NOORDER
+    | DIRECTION
+    | LENGTH
+    | LANGUAGE
     // etc
     ;
 

sql/snowflake/examples/create_table.sql

@@ -94,4 +94,5 @@ create or replace table tz1(i TIMESTAMPLTZ);
 create or replace table tz2(i TIMESTAMPNTZ);
 create or replace table tz3(i TIMESTAMPTZ);
 CREATE TABLE TESTSEED2 (ident int IDENTITY INCREMENT 2 ORDER);
-CREATE TABLE TESTSEED2 (ident int IDENTITY START = 2 INCREMENT BY 1 NOORDER);
+CREATE TABLE TESTSEED2 (ident int IDENTITY START = 2 INCREMENT BY 1 NOORDER);
+CREATE TABLE DIRECTION (LENGTH INT,LANGUAGE INT);