DOC: Improve describe() documentation
- [x] closes #40972 
- [ ] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry


It feels more verbose, but necessary?
Test failure seems unrelated Yeah this test is flaky Thanks for looking at this @Bharat123rox. This patch doesn't look to be addressing the issue - the line before already says that different pandas operations might return a Series or DataFrame. 

The issue here is that the next line mentions that this is an example of a Series being returned, but a DataFrame is actually being returned from this describe example > The issue here is that the next line mentions that this is an example of a Series being returned, but a DataFrame is actually being returned from this describe example

So should we just stick to this example and change it to `DataFrame` because the given `describe()` operation can still return both right? So what should be done then? I would agree with just mentioning DataFrame and Series, e.g. removing the column reference. Do you agree @mzeitlin11? > I would agree with just mentioning DataFrame and Series, e.g. removing the column reference. Do you agree @mzeitlin11?

Updated, please re-review Thanks @Bharat123rox 