cmd/gofmt: don't rewrite into smart quotes

// This program shows that go/format no longer rewrites plain quotes into smart quotes.
// It formats a source string that contains smart quotes and prints the result unchanged.
package main

import (
	"fmt"
	"go/format"
)

func main() {
	// Source code with smart quotes (U+201C and U+201D) in a comment.
	src := []byte(`package main
// “Hello, world!” – a comment with smart quotes
func main() {}`)

	// Format the source. If smart quotes were rewritten, the output would differ.
	formatted, err := format.Source(src)
	if err != nil {
		fmt.Println("format error:", err)
		return
	}

	// Print the formatted source to show that smart quotes are preserved.
	fmt.Println(string(formatted))
}