How to get the type of error to use in error handling

If you do this:

_, err := http.Get("google.com")
if err != nil {
	log.Fatal(err)
}

you get the output:

2021/08/05 15:42:18 Get "google.com": unsupported protocol scheme ""

I'm wondering how do I get the type of error, so I can handle the error like so:

if errors.Is(err, "unsupported protocol scheme") {
	//add protocol scheme to url string
}

I've tried fmt.Printf("%#v", err), which gives:

&url.Error{Op:"Get", URL:"google.com", Err:(*errors.errorString)(0xc000098c40)}

fmt.Printf("%T") gives:

*url.Error

Edit: If you're downvoting, I'd really appreciate a comment with your thoughts.

var e *url.Error
if errors.As(err, &e) && strings.HasPrefix(e.Err.Error(), "unsupported protocol scheme") {
    //add protocol scheme to url string
}

https://play.golang.org/p/VKpMfrBp_EF

Note that comparison against non-standardized strings should not be considered future-proof. For example if a future version of Go decides to change the wording of that error message your code will break.

Although Go does promise compatibility across versions, I don't think that that promise extends to string content.

you can use err.Error() to return string.
and check if it contiane a spicifice keys, something like this:

if err = db.Ping(); err != nil {
    switch {
    case strings.Contains(err.Error(), "connection refused"):
         // handle connection refused. for example:
         cmd := exec.Command("sudo", "service", "mariadb", "start")          
         _ = cmd.Run()
       
    default:
         log.Println("unknown kind of this error", err)
    }
}

in your case you can try somthing like:

err := http.Get(url)

if strings.Contains(err.Error(), "unsupported protocol scheme") {
    //add protocol scheme to url string
}