DOC: Updated resample.py and groupby.py to fix SA04 Errors
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry: Fixed Partial SA04 Errors 


Hello @nagesh-chowdaiah! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



























There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2020-10-23 07:52:28 UTC @simonjayhawkins can you explain me on this test errors.  I just updated the docs and logic is not changed. but still the pipelines are failing @jreback Fixed all the issues or SA04 errors. @jreback and @jorisvandenbossche i have fixed the suggested chagnes. 
 can you merge master and ping on green. Windows py37_np16 unrelated see #37328

```
=========================== short test summary info ===========================
FAILED pandas/tests/computation/test_eval.py::TestEvalNumexprPython::test_binary_arith_ops[4-3-/]
= 1 failed, 96826 passed, 4046 skipped, 1425 xfailed, 1 xpassed, 105 warnings in 1454.58s (0:24:14) =
```

Windows py38_np18 failure 
```
FATAL ERROR: Committing semi space failed. Allocation failed - process out of memory
```

restarting ci
 @jreback and @simonjayhawkins does this needs a wait on #37328 to get merged @jreback can you please merge this PR and can you please add the tag hacktoberfest-accepted. I am participating in that.. would be great if you can help in achieving that target thanks @nagesh-chowdaiah 