DOC: update the pandas.DataFrame.to_sparse docstring (#20193)
DOC: update the pandas.DataFrame.to_sparse docstring (#20193)

* Updates the documentation for pandas.DataFrame.to_sparse.

* Minor fixes and adding more real world examples

pandas-dev/pandas,toobaz/pandas,gfyoung/pandas,gfyoung/pandas,datapythonista/pandas,datapythonista/pandas,TomAugspurger/pandas,cython-testbed/pandas,jreback/pandas,gfyoung/pandas,GuessWhoSamFoo/pandas,kdebrab/pandas,jorisvandenbossche/pandas,cbertinato/pandas,kdebrab/pandas,datapythonista/pandas,harisbal/pandas,harisbal/pandas,kdebrab/pandas,rs2/pandas,harisbal/pandas,dsm054/pandas,datapythonista/pandas,toobaz/pandas,pandas-dev/pandas,toobaz/pandas,MJuddBooth/pandas,cbertinato/pandas,cython-testbed/pandas,cython-testbed/pandas,TomAugspurger/pandas,jreback/pandas,jreback/pandas,cbertinato/pandas,MJuddBooth/pandas,TomAugspurger/pandas,kdebrab/pandas,jreback/pandas,MJuddBooth/pandas,dsm054/pandas,cython-testbed/pandas,jorisvandenbossche/pandas,amolkahat/pandas,jreback/pandas,jorisvandenbossche/pandas,amolkahat/pandas,rs2/pandas,jorisvandenbossche/pandas,dsm054/pandas,kdebrab/pandas,amolkahat/pandas,pandas-dev/pandas,GuessWhoSamFoo/pandas,toobaz/pandas,toobaz/pandas,amolkahat/pandas,harisbal/pandas,pandas-dev/pandas,rs2/pandas,cython-testbed/pandas,MJuddBooth/pandas,gfyoung/pandas,TomAugspurger/pandas,amolkahat/pandas,cbertinato/pandas,GuessWhoSamFoo/pandas,GuessWhoSamFoo/pandas,dsm054/pandas,MJuddBooth/pandas,dsm054/pandas,gfyoung/pandas,cbertinato/pandas,rs2/pandas,GuessWhoSamFoo/pandas,harisbal/pandas