Fix docstrings in pong

* lisp/play/pong.el (pong-move-left pong-move-right): Refer to the
right bats and directions of movement.  (Bug#36959)
1 job for emacs-26 in 50 minutes and 28 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #2945
test

00:50:28

 
Name Stage Failure
failed
test Test
Makefile:285: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:255: recipe for target 'check' failed
make[1]: *** [check] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:951: recipe for target 'check' failed
make: *** [check] Error 2
ERROR: Job failed: exit code 1