Example code on pkg.go.dev site fails in playground

[afninfa]

Hello, I just noticed something that may be a problem, and I thought it could be useful if I let somebody know. I tried to run the example code snippet on the Go documentation website, but it failed in the playground with this error

https://pkg.go.dev/github.com/antchfx/xpath#example-package

I attempted to run the same piece of code on my local machine and got the same error.

[afninfa]

I noticed the exact same code from the documentation website appears in a unit test here

https://github.com/antchfx/xpath/blob/master/doc_test.go#L10

but it seems like this unit test is never run.

[zhengchun]

You should include another package(xmlquery, htmlquery or jsonquery) to run this example.

doc, err := xmlquery.LoadURL("https://www.w3schools.com/xml/books.xml")
if err != nil {
	panic(err)
}
var root xpath.NodeNavigator = xmlquery.CreateXPathNavigator(doc)
// using Evaluate() method
...

I try fixing this example.