DOC: update the pandas.DataFrame.diff docstring (#20227)
DOC: update the pandas.DataFrame.diff docstring (#20227)

* DOC: update the pandas.DataFrame.diff  docstring

* DOC: update the pandas.DataFrame.diff docstring

* DOC: update the pandas.DataFrame.diff docstring

* DOC: update the pandas.DataFrame.diff docstring

* DOC: update the pandas.DataFrame.diff docstring

* DOC: update the pandas.DataFrame.diff  docstring

* DOC: update the pandas.DataFrame.diff  docstring

* DOC: update the pandas.DataFrame.diff  docstring

* DOC: update the pandas.DataFrame.diff docstring

* Cleanup

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