Do not break `.await` in method chains

[RGBCube]

Input:

let foo = foo.bar().await.biz().await.baz().await;

Desired output:

let foo = foo
  .bar().await
  .biz().await
  .baz().await;

Current output:

let foo = foo
  .bar()
  .await
  .biz()
  .await
  .baz()
  .await;

A nightly (or even stable 👀) option to get the Desired output would be really nice. Justification for this is there rarely is anything to do other than .await for the vast majority of async methods, and a newline is extra noise. Putting the .await on the same line signifies a stronger tie to the method and makes it easier to shuffle them around by shifting lines.

I'm willing to work on this, just curious if it has any chance of getting merged.

[ytmimi]

Pretty much a duplicate of #4306. We'd like to give users some more options on how to format chains, but that hasn't been implemented yet.