Problem: filetype: supertux files are not recognized
Solution: Supertux uses lisp to store hotkeys in config and game stage information,
so add a pattern for supertux files.
(Wu, Zhenyu)
Reference: https://github.com/SuperTux/supertux/wiki/S-Expressioncloses: #14356
Signed-off-by: Wu, Zhenyu <wuzhenyu@ustc.edu>
Signed-off-by: Christian Brabandt <cb@256bit.org>