net/netip: ParsePrefix documentation typo "2001::db8::/32"

[alcicd]

What version of Go are you using (go version)?

$ go version
go1.18beta2

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

Not applicable

What did you do?

Read docs/code

What did you expect to see?

Valid CIDR notation

What did you see instead?

Invalid CIDR notation

"2001::db8::/32" includes an invalid IPv6 address. The double colon may appear only once. This code panics:

package main

import (
	"net/netip"
)

// This playground uses a development build of Go:
// devel go1.18-41f485b9a7 Mon Jan 31 13:43:52 2022 +0000

func main() {
	_ = netip.MustParsePrefix("2001::db8::/32")
}

go/src/net/netip/netip.go

Line 1291 in 41f485b

// The string can be in the form "192.168.1.0/24" or "2001::db8::/32",

[gopherbot]

Change https://golang.org/cl/382294 mentions this issue: net/netip: correct ipv6 address in ParsePrefix comment