Single node MappingValue path not set correctly

[LarsStegman]

Describe the bug
MappingValueNode path is set incorrectly when it is the root element. I think the node should get as path $, although I am not 100% certain. At least, the behaviour is not consistent.

To Reproduce
Given this file:

x: 3

You get this AST where the path of the MappingValue is $

Expected behavior
If there is a nested value, the root MappingValue gets a different path, $.x:

x:
  y: 3

Version Variables

• Go version: 1.23
• go-yaml's Version: v1.15.7