removed the use of UT

this was a common abbreviation for the game. But after looking into it the aliases doesn't make sense so it's removed

Co-authored-by: Eric Sorenson <ahpook@github.com>

Author: Drwhomust

topics/undertale/index.md

@@ -2,7 +2,7 @@
 display_name: Undertale
 topic: undertale
 created_by: Toby Fox
-aliases: ut, under-tale
+aliases: under-tale
 related: video-game, role-playing-game, rpg, deltarune, gamemaker, bullet-hell
 short_description: Undertale is a video game created by Toby Fox.
 wikipedia_url: https://en.wikipedia.org/wiki/Undertale