Steps to replicate the issue (include links if applicable):

• Visit mediawikiwiki
• Create or find a talk page with page content mode = flow-board
• Create a thread, with a wikilink pointing at a non-existent userpage, such as [[User:Nardog]]

(Visit https://www.mediawiki.org/wiki/Topic:Xlrhitipsnlphmph for an example)

What happens?:

• Clicking on "Nardog" tries to navigate to the mediawiki page "User:Nardog?action=edit&redlink=1"
• The link renders as https://www.mediawiki.org/w/index.php?title=User:Nardog%3Faction%3Dedit%26redlink%3D1&action=edit&redlink=1

What should have happened instead?:

• Clicking on "Nardog" tries to navigate to the mediawiki page "User:Nardog"
• The link renders as https://www.mediawiki.org/w/index.php?title=User:Nardog&action=edit&redlink=1

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):

• Pings still work