LiteralNode.String() omits trailing blank lines for literal strings

[semihbkgr]

When parsing a multiline string with |+, LiteralNode.Value.Value contains the trailing blank lines, but LiteralNode.String() does not render them.

Is this intentional behavior?

I expected LiteralNode.String() to include these trailing blank lines, because these newlines are part of the AST node and change both the value and the representation in the source.

Go Playground reproduction:

https://go.dev/play/p/Y1m0qWMgymQ

This came up in yamldiff: semihbkgr/yamldiff#60

Example

Input:

description: |+
  one
  two

Observed output:

== raw input ==
01: description: |+$
02:   one$
03:   two$
04: $
05: $
06: $

== AST node type ==
Literal

== node.String() ==
01: |+$
02:   one$
03:   two$

== LiteralNode.Value.Value ==
01: one$
02: two$
03: $
04: $
05: $

Go quoted value: "one\ntwo\n\n\n\n"

LiteralNode.Value.Value includes the trailing blank lines:

"one\ntwo\n\n\n\n"

But node.String() renders only:

|+
  one
  two

[semihbkgr]

I also noticed that node.MarshalYAML() returns YAML that does not include the trailing newlines, which means the resulting YAML has a different value from the original parsed node.

Example: https://go.dev/play/p/ccHwEfPWKWk