Docs: Update use-cases.rst [skip ci] (#4094)
Docs: Update use-cases.rst [skip ci] (#4094)

This PR updates `use-cases.rst` with several corrections and improvements to the text. Because of the amount of changes applied, it is best to take a closer look at them, from top to bottom, to see if they make sense.
ContinuumIO/dask,jakirkham/dask,blaze/dask,dask/dask,jcrist/dask,dask/dask,ContinuumIO/dask,jcrist/dask,blaze/dask,mrocklin/dask,jakirkham/dask,mrocklin/dask