interleave whitespace between recursive let and module bindings

[IwanKaramazow]

Fixes #1958

[chenglou]

Should we even allow whitespace between recursive let bindings? As much as possible I'd still like us to be opinionated on whitespace

[IwanKaramazow]

I think we should for consistency, it would be a little bit weird if we didn't allow it here.
Imagine rewriting the Reason printer with recursive functions instead of using the object system:

let rec printExpression = (e) => beatifulPrinting(e)

and printPattern = (pat) => ...

and printModule = (m) => ...

Some space between the different bindings gives a little more room to breath

[chenglou]

Would this actually happen though? Because the reality would be:

let rec printExpression = (e) => {
  beatifulPrinting(e)
  ...
}
and printPattern = (pat) => {
  ...
}
and printModule = (m) => {
   ...
}

Right?

[IwanKaramazow]

Yes, but someone might want to write the following:

let rec main = (e) => {
  ...
}

and helper1 = (_) => {
  ...
}
and helper2 = (_) => {
   ...
}
and helper3 = (_) => {
   ...
}

helper1, helper2, helper3 could be grouped together. Visually it becomes very clear what the relation between the helper{X} and main is.

I might be completely wrong though, no opinion, and can close the PR.

[jaredly]

I have a mild preference for keeping recursive bindings together