Support QUALIFY clause in Snowflake

Fixes #539

Author: nene

src/languages/snowflake/snowflake.formatter.ts

@@ -14,6 +14,7 @@ const reservedClauses = expandPhrases([
   'HAVING',
   'PARTITION BY',
   'ORDER BY',
+  'QUALIFY',
   'LIMIT',
   'OFFSET',
   'FETCH [FIRST | NEXT]',

test/snowflake.test.ts

@@ -90,6 +90,17 @@ describe('SnowflakeFormatter', () => {
     `);
   });
 
+  it('supports QUALIFY clause', () => {
+    expect(format(`SELECT * FROM tbl QUALIFY ROW_NUMBER() OVER my_window = 1`)).toBe(dedent`
+      SELECT
+        *
+      FROM
+        tbl
+      QUALIFY
+        ROW_NUMBER() OVER my_window = 1
+    `);
+  });
+
   it('formats ALTER TABLE ... ALTER COLUMN', () => {
     expect(
       format(