Add basement-swim page linked from  eating-chocolate page

I modified 'english/light-fire/sprinkler/eating-chocolate.md'. Now the basement is flooded with chocolate and there is one more choice (swim in the chocolate pool), which means there is another subdirectory and page added (basement-swim/basement-swim.md).
Please don't include blank lines in the middle of a sentence, since it looks strange to have a lot of white space in the middle of the sentence.  It's good that you broke up this sentence to be on multiple lines, just delete the blank lines (lines 2 and 4).