DOC: improved the scatter method
Checklist for the pandas documentation sprint (ignore this if you are doing
an unrelated PR):

- [x] PR title is "DOC: update the <your-function-or-method> docstring"
- [x] The validation script passes: `scripts/validate_docstrings.py <your-function-or-method>`
- [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 <your-function-or-method>`
- [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.DataFrame.plot.scatter)  ##################
################################################################################

A scatter plot with point size *s* and color *c*.

The coordinates of each point *x,y* are defined by two dataframe
columns and filled circles are used to represent each point.

Parameters
----------
x : column name or column position
    Horizontal and vertical coordinates of each point.
y : column name or column position
    Vertical coordinates of each point.
s : scalar or array_like, optional
    Size of each point.
c : label, column name or column position, optional
    Color of each point.
kwds : optional
    Keyword arguments to pass on to :py:meth:`pandas.DataFrame.plot`.

Returns
-------
axes : matplotlib.AxesSubplot or np.array of them

See Also
--------
matplotlib.pyplot.scatter : scatter plot using multiple input data
    formats.

Examples
--------

.. plot::
    :context: close-figs

    >>> from sklearn.datasets import load_iris
    >>> iris = load_iris()
    >>> df = pd.DataFrame(iris.data[:,:2],
    ...                   columns=iris.feature_names[:2])
    >>> df['species'] = load_iris().target
    >>> f = df.plot.scatter(x='sepal length (cm)',
    ...                     y='sepal width (cm)',
    ...                     c='species',
    ...                     colormap='viridis')

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

Docstring for "pandas.DataFrame.plot.scatter" correct. :)

```

If the validation script still gives errors, but you think there is a good reason
to deviate in this case (and there are certainly such cases), please state this
explicitly.
FTR this is pandas.DataFrame.plot.scatter. Hello @DaniGate! Thanks for updating the PR.



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

##### Comment last updated on March 14, 2018 at 12:57 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20118?src=pr&el=h1) Report
> Merging [#20118](https://codecov.io/gh/pandas-dev/pandas/pull/20118?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/21ae073671983192f0d7384e4dacca713a6bb04f?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/20118/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/20118?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #20118   +/-   ##
=======================================
  Coverage   91.76%   91.76%           
=======================================
  Files         150      150           
  Lines       49151    49151           
=======================================
  Hits        45102    45102           
  Misses       4049     4049
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.14% <ø> (ø)` | :arrow_up: |
| #single | `41.9% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20118?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/plotting/\_core.py](https://codecov.io/gh/pandas-dev/pandas/pull/20118/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb3JlLnB5) | `82.27% <ø> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/20118/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZWxpa2UucHk=) | `96.72% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/20118/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `95.64% <0%> (ø)` | :arrow_up: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/20118/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `95.85% <0%> (ø)` | :arrow_up: |

------

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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20118?src=pr&el=footer). Last update [21ae073...15b6073](https://codecov.io/gh/pandas-dev/pandas/pull/20118?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 This is almost done I believe, just a couple of style fixes and IMO it will be good to merge. :) Thanks @DaniGate and @dukebody .

Fixed the line length issue. OK, also split the examples in two to be a little clearer. Merging, thanks!