Update marker types to reflect new vision sytem

Author: Tyler-Ward

comp/game/markers.yaml

@@ -7,10 +7,5 @@ component: Competition
 milestone: $SRYYYY Competition
 
 description: >-
-  The arena (and, possibly, things inside it) is marked with libkoki
+  The arena (and, possibly, things inside it) is marked with AprilTag
   markers, which need printing off in advance.
-
-  For the arena itself SR has some pre-printed libkoki markers on a
-  plastic backing which are re-used each year. These need checking
-  and ensuring they make it to the venue. Replacements may be needed
-  for any markers which are showing wear.