Auto-complete inserts arguments in front of the selected text instead of replacing it

The bug

When selecting an argument from the arguments selection that shows up while typing a command, the argument is inserted in front of the currently selected text, instead of replacing the currently selected text. This causes invalid arguments to show up.

Videos

• /tp: https://clips.twitch.tv/DifficultMushyEggnogBudStar
• /execute if entity: Minecraft 20w08a - Singleplayer 2020-02-22 16-15-44.mp4
• /setblock: Minecraft 20w08a - Singleplayer 2020-02-22 16-17-37.mp4