Typo fix in 1991/dds/LANDER.BAS

Although one could get away with saying 'aboard' to mean 'getting on a
ship' ('I climbed aboard the ...') it's probably better to say 'board'
as the verbal form especially in the way it was and is worded (now 'You
board ...'). I believe I already did this change in 1990/dds/LANDER.BAS.

1991/dds/LANDER.BAS

@@ -1,7 +1,7 @@
 10 REM Lunar Lander
 20 REM By Diomidis Spinellis
 25 REM Compiler version
-30 PRINT "You aboard the Lunar Lander about to leave the spacecraft."
+30 PRINT "You board the Lunar Lander about to leave the spacecraft."
 60 GOSUB 4000
 70 GOSUB 1000
 80 GOSUB 2000

thanks-for-fixes.md

@@ -824,6 +824,8 @@ The key to the string is that it rotates the character by `+1`. This was not
 immediately clear until reading the author's remarks so there was an alt version
 that was something of a kludge, running `make a` instead.
 
+Cody also fixed a typo in LANDER.BAS.
+
 
 ## [1991/fine](1991/fine/fine.c) ([README.md](1991/fine/README.md))