DOC: Improved the docstring of Series.any()
Checklist for the pandas documentation sprint (ignore this if you are doing
an unrelated PR):

- [x] PR title is "DOC: Improved the docstring of Series.any()"
- [ ] The validation script passes: `scripts/validate_docstrings.py Series.any()`
- [x] The PEP8 style check passes: `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] The html version looks good: `python doc/make.py --single Series.any()`
- [x] It has been proofread on language by another sprint participant

Please include the output of the validation script below between the "```" ticks:

```
################################################################################
######################## Docstring (pandas.Series.any)  ########################
################################################################################

Return whether any element is True over requested axis.

Returns True if one (or more) elements are non-zero,
not-empty or not-False.

Parameters
----------
axis : {index (0)}
skipna : boolean, default True
    Exclude NA/null values. If an entire row/column is NA, the result
    will be NA.
level : int or level name, default None
    If the axis is a MultiIndex (hierarchical), count along a
    particular level, collapsing into a scalar.
bool_only : boolean, default None
    Include only boolean columns. If None, will attempt to use everything,
    then use only boolean data. Not implemented for Series.
**kwargs : Additional keywords have no effect but might be accepted for
    compatibility with numpy.

Returns
-------
any : scalar or Series (if level specified)

Examples
--------
>>> s1 = pd.Series([1, 2, 3])
>>> s1.any()
True

>>> import numpy as np
>>> s2 = pd.Series([np.NaN, np.NaN, np.NaN])
>>> s2.any()
False

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

Errors found:
        Errors in parameters section
                Parameters {'kwargs'} not documented
                Unknown parameters {'**kwargs'}
                Parameter "axis" has no description
                Parameter "**kwargs" description should start with capital letter
        See Also section not found
```

Participants of the documentation sprint were told to go ahead with the description of the "**kwargs" parameter. 

Parameter "axis" has no description looks like a bug to me. Noticed some other methods show the same validation error. e.g "pandas.Series.mean" throws the same validation error.
Does this close a specific issue? # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=h1) Report
> Merging [#20078](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/731d97164ba04150174c4e05f56d40f716044219?src=pr&el=desc) will **increase** coverage by `0.02%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/20078/graphs/tree.svg?height=150&src=pr&width=650&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #20078      +/-   ##
==========================================
+ Coverage    91.7%   91.72%   +0.02%     
==========================================
  Files         150      150              
  Lines       49122    49149      +27     
==========================================
+ Hits        45045    45083      +38     
+ Misses       4077     4066      -11
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.11% <ø> (+0.02%)` | :arrow_up: |
| #single | `41.85% <ø> (-0.02%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/20078/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `95.84% <ø> (ø)` | :arrow_up: |
| [pandas/core/groupby.py](https://codecov.io/gh/pandas-dev/pandas/pull/20078/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS5weQ==) | `92.14% <0%> (-0.01%)` | :arrow_down: |
| [pandas/io/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/20078/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2h0bWwucHk=) | `86.6% <0%> (+0.62%)` | :arrow_up: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/20078/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `66.81% <0%> (+1.73%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=footer). Last update [731d971...680f48c](https://codecov.io/gh/pandas-dev/pandas/pull/20078?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @FrankDupree can you please read carefully the doc on how to submit a PR [1], and make sure you do all the steps correctly? You surely missed the point about the title of the PR, and also copying the output of the `validate_docstrings.py` in the description. Without those, it's difficult to understand what you sent and review it.

Btw, in the description of the PR, the `[ ]` are checkboxes. You should make sure you completed every listed point, and mark them with an `[X]`, so we know you did.

Thank you!

1. https://python-sprints.github.io/pandas/guide/pandas_pr.html Are ``Parameter "axis" has no description`` and ``See Also section not found`` solved? If yes, could you update the description? Please update the description with the validation script output
 @FrankDupree Some things have changed in master. Can you check if there's anything else to be done? @TomAugspurger I will.  So it seems we had a conflicting PR https://github.com/pandas-dev/pandas/pull/20217 that implemented `DataFrame.any`, and since Series and DataFrame share code, this might have been duplicate work .. Sorry about that! 

I am going to close this PR, but please check if there is anything in your PR that is not in http://pandas-docs.github.io/pandas-docs-travis/generated/pandas.Series.any.html#pandas.Series.any. 
For example, I think it would be good to add an example of what an empty Series returns (Series([]).any()). Feel free to open a PR for that.
