Sentence restructured in compare methods's doc
A sentence from section [Merge, join, concatenate and compare](https://pandas.pydata.org/docs/user_guide/merging.html#) in user guide doc -specifically in [DataFrame.compare()](https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.compare.html#pandas.DataFrame.compare) method's  docs,has been restructured so that it is more easy to comprehend ,earlier more obscure sentence has now been simplified by just adding few words more 

Thanks @imTejasRajput 