x/website: https://golang.org/doc/tutorial/greetings-multiple-people should highlight added code

[apuchitnis]

Specifically the following code under step 2 should be highlighted in blue:

    // Request greeting messages for the names.
    messages, err := greetings.Hellos(names)
    if err != nil {
        log.Fatal(err)
    }

Does this issue reproduce with the latest release?

Yes, https://golang.org/doc/tutorial/greetings-multiple-people as of today.

What did you expect to see?

New code is highlighted.

What did you see instead?

New code that isn't highlighted.

[seankhliao]

Duplicate of #46416