Added docs to fix GL08 errors in CustomBusinessHours

[mohdkashif93]

• xref DOC: Fix formatting errors in docstrings #27977
• tests added / passed
• passes black pandas
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

Currently even after adding the docstrings the command python scripts/validate_docstrings.py --errors=GL08 does not pick up the changes.

[jreback]

Currently even after adding the docstrings the command python scripts/validate_docstrings.py --errors=GL08 does not pick up the changes.

not sure we are checking this yet (idea is to fix the errors then add the check). dependens on how much fails across the codebase.

[MarcoGorelli]

not sure we are checking this yet (idea is to fix the errors then add the check). dependens on how much fails across the codebase.

There are still lots of GL08 errors in many files, so adding this error to the check would require lots more docstrings.

Though this

Currently even after adding the docstrings the command python scripts/validate_docstrings.py --errors=GL08 does not pick up the changes.

may require further investigation, not sure why it wouldn't pick up the changes (this happened even after running python setup.py build_ext -i -j 4)

[jreback]

thanks @mohdkashif93