minor fixes

minor immediate fixes
You need to edit the previous choices - that allows to know the full history if needed, for example in events.

Edit: ah, I see why you did it - you're missing the `reversed(...)` in the for loop at https://github.com/edx-solutions/xblock-adventure/pull/10/files#diff-6d8a066f5c5274de4b46de92bb98eab2R206 which allows to pick the last choice. See https://github.com/edx-solutions/xblock-adventure/pull/8/files#r18387894