Adjust formatting of line comments in lets

[bioball]

Fixes an issue where line comments preceding let bodies are not indented.

Turn this:

bar3 =
  let (bar = new Dynamic {})
  // some coment
    (bar) {
      qux = 4
    }

Into this:

bar3 =
  let (bar = new Dynamic {})
    // some coment
    (bar) {
      qux = 4
    }

[stackoverflow]

Almost there, but you can't rely on next?.type == LET_EXPR because you might have more than one comment (in fact you should add this case to the tests):

let (x = 1)
  // comment1
  // comment2
  x

Probably easier to check if the expression is another let and just indent based on that:

private fun formatLetExpr(node: Node): FormatNode {
    val endsWithLet = node.children.last().type == NodeType.LET_EXPR
    val nodes =
      formatGenericWithGen(
        node.children,
        { _, next -> if (next.type == NodeType.LET_PARAMETER_DEFINITION) Space else spaceOrLine() },
      ) { node, _ ->
        when {
          node.type == NodeType.LET_EXPR -> {
            // unpack the lets
            val group = formatLetExpr(node) as Group
            Nodes(group.nodes)
          }
          endsWithLet -> format(node)
          node.type.isExpression || node.type.isAffix -> indent(format(node))
          else -> format(node)
        }
      }
    return Group(newId(), nodes)
  }

[bioball]

Ah, thanks!

[stackoverflow]

Looks good!