Format DEFAULT VALUES clause for Postgres (#720)

Closes #718.

Author: nene

src/languages/postgresql/postgresql.formatter.ts

@@ -23,6 +23,7 @@ const reservedClauses = expandPhrases([
   // - insert:
   'INSERT INTO',
   'VALUES',
+  'DEFAULT VALUES',
   // - update:
   'SET',
   // other

test/postgresql.test.ts

@@ -331,4 +331,18 @@ describe('PostgreSqlFormatter', () => {
         release;
     `);
   });
+
+  it('formats DEFAULT VALUES clause', () => {
+    expect(
+      format(`INSERT INTO items default values RETURNING id;`, {
+        keywordCase: 'upper',
+      })
+    ).toBe(dedent`
+      INSERT INTO
+        items
+      DEFAULT VALUES
+      RETURNING
+        id;
+    `);
+  });
 });