message: js-generator: Fix double indent for type unions
diff: @@ -13,17 +13,12 @@ export default function UnionTypeAnnotation(generator: Generator, node: AnyNode)
  generator.multiline(node, (multiline, node) => {
  if (multiline) {
  - generator.indent();
  orNewlineSeparator(generator, false);
  }
  generator.printJoin(node.types, node, {
  after: multiline ? orNewlineSeparator : orSpaceSeparator,
  });
  -
  - if (multiline) {
  - generator.dedent();
  - }
  }, {conditions: ['more-than-one-line'], indent: true});
  }
  