Disable autofill of forms

In Microsoft Edge Insider (dev branch), when I type into a text box in a form, a drop-down sometimes appears containing all prior values I ever typed into that textbox. I cannot remove entries from the drop-down, nor can I disable the drop-down entirely. I looked at edge://flags, but nothing jumped out at me (most autofill options had to do with credit-card forms, which is not what I am dealing with here), and the few options that seemed relevant did nothing. I would greatly appreciate it if this drop-down can be permanently disabled for all websites, as I do not like it one bit.

Steps to reproduce:

1. Go to https://chocolatey.org/ (this is where I saw the issue)
2. Click in the search box at the top of the page. Type something ("paint.net", for example), and press Enter.
3. Open a new tab, and go to https://chocolatey.org/ again.
4. Click in the search box, and observe the pop-up that appears with the previous values typed into that search box.