I can't state how much I dislike most (if not all) of these auto-smart corrections. In my case, even a simple number was automatically turned into a link, and I don't even want to know what it links to... Anyway, here's how I removed it in the web tool: click the "..." button just to the right of the bold-italic-underline group. A submenu opens, including "link" and "unlink" buttons. Just click the "unlink" button.