How it's supposed to work:

1. Open a page in VisualEditor.
2. Paste a URL in like this one: https://en.wikipedia.org/wiki/National_Register_of_Historic_Places_listings_in_Concord,_Massachusetts
3. Rejoice in the the magically converted wikilink.

How it's actually working, if the URL contains percent encoding:

1. Open a page in VisualEditor.
2. Paste a URL in like this one: https://en.wikipedia.org/wiki/Wright%27s_Tavern
3. Realize that the only way to 'fix' it is to delete that, type the desired label, select it, open the link tool, and search for a link the usual way.