Tutorial part 10 refers to incorrect filename in data_loaders.py

[abwdev]

Hi,

First up - FREAKING AWESOME TUTORIAL!!!! THANK YOU SO MUCH!!! - seriously the BEST roguelike tute I've encountered.

I think that part 10 of the tutorial (http://rogueliketutorials.com/tutorials/tcod/part-10/) incorrectly includes the file type suffix in two places within data_loaders.py - specifically in save_game for the call to write out the data, and also in load_game for the call to read in the data.

I believe that this is because Python automatically appends the ".dat" to those calls, whereas in the filesystem check to verify the save file the ".dat" is required.

You have corrected this in the GitHub repo but not in the tutorial text which could throw folks (it confused me :) )

Thanks again!