DOC: update examples in MonthBegin/MonthEnd to use rollbackward/rollforward

[pranav-ravuri]

• closes DOC: MonthBegin suggestion to get start of current month not quite right? #52106
  updated docstring of pandas.offsets.MonthBegin, pandas.offsets.MonthEnd, pandas.offsets.BMonthBegin, pandas.offsets.BMonthEnd
  the output of the validate_docsctrings.py is similar to the below output as follows

################################################################################
#################### Docstring (pandas.offsets.MonthBegin)  ####################
################################################################################

DateOffset of one month at beginning.

Examples
--------
>>> ts = pd.Timestamp(2022, 1, 1)
>>> ts + pd.offsets.MonthBegin()
Timestamp('2022-02-01 00:00:00')

################################################################################
################################## Validation ##################################
################################################################################

2 Errors found:
        No extended summary found
        See Also section not found

[MarcoGorelli]

This is a great first contribution, thanks @pranav-ravuri ! Looks good to me pending green

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 2.0.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 4bf60ac2bab5878c1a0f640ab826df77a77f7e98

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #52161: Docs/update issue 52106'

4. Push to a named branch:

git push YOURFORK 2.0.x:auto-backport-of-pr-52161-on-2.0.x

5. Create a PR against branch 2.0.x, I would have named this PR:

"Backport PR #52161 on branch 2.0.x (Docs/update issue 52106)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[MarcoGorelli]

@pranav-ravuri there's one more related one, in case you wanted to take this one on #52169

[pranav-ravuri]

Hi @MarcoGorelli there seems to be conflict, but I did not understand what it is? And how could I have avoided it?

[MarcoGorelli]

the conflict is only when backporting to version 2.0 (from which the next stable docs will be built) - you did everything right, it's just that not everything gets backported, so conflicts creep in sometimes