48779-doc-MonthEnd
- [x] closes #48779
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
As proposed by @MarcoGorelli I updated docs for `MonthEnd` and added one more example to highlight “the last day of the month” behavior.

I checked that build of documentation shows the new description.
Thank you @MarcoGorelli, for your comments and hints. I corrected my docstring and added an example, which uses `n=0`

Unfortunately, my docker environment is broken by absence of visioner.py and I can not validate my changes locally.
If I am not mistaken, visioner.py is missing after recent commit: BLD: use nonvendor versioneer (#49924) thanks for updating!

could you try updating your environment? `versioneer` was added to the `environment.yml` file in that PR. I don't know about how it works in the Docker container, but for me `mamba env update -n pandas-dev --file environment.yml` worked Assuming you are using the Dockerfile in this repo, a force rebuild of the image should pick up the versioneer dependency > Assuming you are using the Dockerfile in this repo, a force rebuild of the image should pick up the versioneer dependency

Thank you @WillAyd, I fixed my problem with docker image. > could you try updating your environment? `versioneer` was added to the `environment.yml` file in that PR. I don't know about how it works in the Docker container, but for me `mamba env update -n pandas-dev --file environment.yml` worked

Thank you, @MarcoGorelli, my environment works well now. I fixed errors in docs for `MonthEnd` and added an example for `n=0`. Docstring validation also requested me to add `See Also` section. I added the reference to `DateOffset`.

I noticed one check during CI failed, but I assume it was caused by timeout and not by my changes.
 > If there's other DateOffsets where similar confusion can arise, PRs to add examples / clarification there too would be welcome
> 
Certainly. Checking other DateOffsets looks like a good idea. I will look into it.
> Regarding the "see also" note - this isn't strictly necessary to pass CI, as the codes in
> 
> https://github.com/pandas-dev/pandas/blob/4d0a4365870893e232f639af13fea44c7d3ff9d4/ci/code_checks.sh#L83
> 
> are currently checked - but it's nice to have it anyway, thanks!
> 
I will use the same list of errors locally the next time.

Thank you @MarcoGorelli, for your guidance and support. It makes contributing to pandas pleasant and not too complicated.
