[Diagnostics] Intra-group trivia not preserved when moving a node group

[AppAppWorks]

Description

When a Fix-it moves a group of consecutive nodes, the intra-group trivia won't be preserved,

func test() -> throws(any /**/ Error) Int
// after Fix-it
func test() throws(any Error) -> Int

It's because the nodes aren't actually "moved" when applying a Fix-it. Rather the misplaced nodes carrying the trivia are removed, and the missing nodes created by the parser (without the trivia) are presented at the designated site.

Currently trivia at the sides of a node group to move are transferred to its adjacent tokens, we should create facilities to transfer intra-group trivia from the misplaced nodes to the missing nodes.

Steps to Reproduce

No response

[ahoppen]

Synced to Apple’s issue tracker as rdar://135922636