DOC: DataFrame.merge behaviour for suffix=(False, False)
- [x] closes #22045
- N/A tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- N/A whatsnew entry
Hello @elmq0022! Thanks for updating the PR.



Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on August 24, 2018 at 23:57 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22141?src=pr&el=h1) Report
> Merging [#22141](https://codecov.io/gh/pandas-dev/pandas/pull/22141?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/55d176d1cd624f8921379c0ceed06fb8e00625b9?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

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|---|---|---|
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 @jreback, I updated the docstring with a couple suffix examples.   @jreback any additional feedback?  Thanks! Sure.

On Mon, Aug 20, 2018, 5:39 PM Jeff Reback <notifications@github.com> wrote:

> *@jreback* requested changes on this pull request.
> ------------------------------
>
> In pandas/core/frame.py
> <https://github.com/pandas-dev/pandas/pull/22141#discussion_r211429185>:
>
> > @@ -254,6 +255,23 @@
>  3  foo        5  foo        8
>  4  bar        2  bar        6
>  5  baz        3  baz        7
> +
> +>>> A.merge(B, left_on='lkey', right_on='rkey', how='outer',
>
> can you add a comment for both of these example of what they are showing
>
> —
> You are receiving this because you were mentioned.
> Reply to this email directly, view it on GitHub
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>
 @jreback and @datapythonista, I added comments to the examples.   @datapythonista, I made the updates.  This should be good to go now.  Thanks! @datapythonista I made the updates.   @jreback, @datapythonista two items to address:

First, the following Travis job is failing.  

43166.3
Python: 3.5
JOB="2.7, locale, slow, old NumPy" ENV_FILE="ci/travis-27-locale.yaml" LOCALE_OVERRIDE="zh_CN.UTF-8" SLOW=true
3 min 51 sec

The error message is:
ImportError: libgfortran.so.1: cannot open shared object file: No such file or directory.  

I don't think this error is on my end, but let me know if I have to do something differently.  I did just rebase and rebuild all the C extensions.  

Second, I think I get what @jreback was referring to prior.  I am not sure if the pandas.DataFram.merge doctests are necessarily run during CI.  In doctests.sh on line 23 there is no *merge* argument mentioned. 

```bash
pytest --doctest-modules -v pandas/core/frame.py \
        -k"-assign -axes -combine -isin -itertuples -join -nlargest -nsmallest -nunique -pivot_table -quantile -query -reindex -reindex_axis -replace -round -set_index -stack -to_dict -to_stata -transform"
```
Should we add it here between -join and -nlargest?  Not sure where else this would go or what else would kick off the tests.   @elmq0022 the CI error seems indeed unrelated to your changes. About the doctests, the `-` in `-join -nlargest ...` means that the tests are being skipped. So, that list is the list of tests that are failing now. If `-merge` is not there means that the examples are already correct, so as far as they continue to be correct, nothing needs to be done (if you have a example that breaks or with output different than what presented, the CI should report it). @datapythonista @jreback, thanks for all your help.  Will need to rebase and resubmit to pass the CI? Yes, if you can merge master into your branch and push, that should trigger the CI again. @jreback and @datapythonista all green.  @jreback friendly reminder. Thanks! Thanks for the work on this @elmq0022  @datapythonista no problem.  Happy to help.  Thanks for feedback and merging the request. 