replaced one occurrence of `Appender` by `doc` decorator
- [X] xref #31942
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] replaces one use of `Appender` in pandas/core/generic.py with `doc`

Can you post a screenshot of the built docs to be sure? Otherwise lgtm

@datapythonista  > Can you post a screenshot of the built docs to be sure? Otherwise lgtm
> 
> @datapythonista

Following these instructions https://pandas.pydata.org/docs/development/contributing.html#updating-a-pandas-docstring I get the following error:

```
....
Generating code
Finished generating code
_cython_magic_7cfcd297cf3589fb82aadc28e5e69065.c
c:\users\david\virtualenvs\pandas-dev\lib\site-packages\numpy\core\include\numpy\npy_1_7_deprecated_api.h(14) : Warning Msg: Using deprecated NumPy API, disable it with #define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
C:\Users\David\.ipython\cython\_cython_magic_7cfcd297cf3589fb82aadc28e5e69065.c(2063): warning C4244: '=': conversion from 'Py_ssize_t' to 'int', possible loss of data
   Creating library C:\Users\David\.ipython\cython\Users\David\.ipython\cython\_cython_magic_7cfcd297cf3589fb82aadc28e5e69065.cp37-win_amd64.lib and object C:\Users\David\.ipython\cython\Users\David\.ipython\cython\_cython_magic_7cfcd297cf3589fb82aadc28e5e69065.cp37-w
in_amd64.exp
Generating code
Finished generating code
reading sources... [ 97%] user_guide/io

>>>-------------------------------------------------------------------------
Exception in C:\Users\David\source\repos\pandas-smartvinnetou\doc\source\user_guide\io.rst at block ending on line None
Specify :okexcept: as an option in the ipython:: block to suppress this message
---------------------------------------------------------------------------
PermissionError                           Traceback (most recent call last)
<ipython-input-195-0921b9172ac8> in <module>
----> 1 os.remove('tmp.sv')

PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'tmp.sv'
<<<-------------------------------------------------------------------------



>>>-------------------------------------------------------------------------
Exception in C:\Users\David\source\repos\pandas-smartvinnetou\doc\source\user_guide\io.rst at block ending on line 1768
Specify :okexcept: as an option in the ipython:: block to suppress this message
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-196-dcf9a3f04fb4> in <module>
----> 1 json = dfj.to_json()

~\source\repos\pandas-smartvinnetou\pandas\core\generic.py in to_json(self, path_or_buf, orient, date_format, double_precision, force_ascii, date_unit, default_handler, lines, compression, index, indent)
   2339             compression=compression,
   2340             index=index,
-> 2341             indent=indent,
   2342         )
   2343

~\source\repos\pandas-smartvinnetou\pandas\io\json\_json.py in to_json(path_or_buf, obj, orient, date_format, double_precision, force_ascii, date_unit, default_handler, lines, compression, index, indent)
     82         default_handler=default_handler,
     83         index=index,
---> 84         indent=indent,
     85     ).write()
     86

~\source\repos\pandas-smartvinnetou\pandas\io\json\_json.py in write(self)
    142             self.date_format == "iso",
    143             self.default_handler,
--> 144             self.indent,
    145         )
    146
.....
```
Lot more similar errors follow. I am on Windows 10 Home edition.
 Thanks for the work on this @smartvinnetou 

I think it's known that the documentation has some problems in Windows. We wanted to fix them and build the docs on Windows in the CI, but that didn't happen. Feel free to have a look, but as far as it works in the CI we can move forward.