Split lines in README

https://github.com/NovakLabOSU/FracFeedExtractor/blob/f0c6492f0f481a3ddca1559d15a437567af3dea2/README.md?plain=1#L116

I suggest splitting this cell into two cells.  The model needs to be downloaded before `list` will work, so having a user copy-paste as a single cell returns `not enough directory stack entries.`