Seems Like the recommendation changed from supporting ; and & to only using &.
Thinking about it, it is a little surprising as, if I remember correctly, in HTML source you should encode & as & right?
& as an escape character only applies to text nodes. Of course, if you want to display the URL on a page, you have to escape it, but not in the href.
& as an escape character only applies to text nodes. Of course, if you want to display the URL on a page, you have to escape it, but not in the href.