fix(dialect): reduce MariaDB CONNECT BY hint weight to 2 so Oracle wins pure CONNECT BY queries

Oracle's CONNECT BY weight is 3; MariaDB's was also 3, causing a tie broken
by non-deterministic map iteration. Reducing MariaDB to weight 2 ensures
Oracle wins when CONNECT BY is the only hint. MariaDB is still correctly
detected when its unique high-weight hints (NEXTVAL, FOR SYSTEM_TIME, etc.)
are present.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: 2 people

pkg/sql/keywords/detect.go

@@ -85,7 +85,7 @@ var dialectHints = []dialectHint{
 	{pattern: "SYSTEM VERSIONING", dialect: DialectMariaDB, weight: 5},
 	{pattern: "FOR SYSTEM_TIME", dialect: DialectMariaDB, weight: 5},
 	{pattern: "VERSIONING", dialect: DialectMariaDB, weight: 4},
-	{pattern: "CONNECT BY", dialect: DialectMariaDB, weight: 3},
+	{pattern: "CONNECT BY", dialect: DialectMariaDB, weight: 2},
 	{pattern: "CREATE SEQUENCE", dialect: DialectMariaDB, weight: 5},
 	{pattern: "DROP SEQUENCE", dialect: DialectMariaDB, weight: 5},