swift format fails when using new `sending` keyword. ### Steps To Reproduce: 1. Create a Foo.swift with following content and save: ``` struct Foo { var bar: String } func whatever(_ foo: sending Foo) { } ``` 2. Run `swift format Foo.swift` on cli. ### Results: #### Observed: Invocation fails: /Users/fabian/Developer/test.swift:5:30: error: unexpected code 'Foo' in parameter clause. #### Expected: `swift format` succeeds. ### Notes: Fails with Swift from Xcode-beta and swift-6.0-nightly on linux.