Cope with YAML idiosyncracy at unquoted "YES".

adventure.yaml

@@ -3997,7 +3997,7 @@ actions: !!omap
     message: 'Wizards are not to be disturbed by such as you.'
     words: ['wizar']
     noaction: true
-- YES:
+- "YES":
     message: 'Guess again.'
     words: ['yes']
     noaction: true

make_dungeon.py

@@ -317,7 +317,7 @@ def buildtravel(locs, objs):
     # THIS CODE IS WAAAY MORE COMPLEX THAN IT NEEDS TO BE.  It's the
     # result of a massive refactoring exercise that concentrated all
     # the old nastiness in one spot. It hasn't been finally simplified
-    # because there's no need to do it until one of the asserions
+    # because there's no need to do it until one of the assertions
     # fails. Hint: if you try cleaning this up, the acceptance test is
     # simple - the output dungeon.c must not change.
     #