Node.replaceWith() within a function removes preceding spaces

[nex3]

• Operating System (or Browser): RunKit
• Node Version: 10.18.0
• postcss-values-parser Version: 3.0.5

How Do We Reproduce?

https://runkit.com/nex3/5e2ec2c236cf0f001ac9f9ab

var {parse} = require("postcss-values-parser")

var result = parse("fn(foo bar)");
result.nodes[0].nodes[1].replaceWith(parse("baz"));
result.toString();

Expected Behavior

This should return "fn(foo bar)".

Actual Behavior

It returns "fn(foobar)".