DOC/CLN: Fix various docstring errors
This PR fixes a variety of docstring errors found in different parts of the code base (mostly incorrect names for data types, missing punctuation, PEP8 in examples, etc.).
Hello @dsaxton! Thanks for updating the PR.





















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

##### Comment last updated on February 16, 2019 at 13:35 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=h1) Report
> Merging [#25295](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4d44a2aff08c3075d9472e361bd7448a0472494e?src=pr&el=desc) will **decrease** coverage by `49.99%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25295/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #25295      +/-   ##
==========================================
- Coverage   91.72%   41.72%     -50%     
==========================================
  Files         173      173              
  Lines       52831    52831              
==========================================
- Hits        48457    22045   -26412     
- Misses       4374    30786   +26412
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `?` | |
| #single | `41.72% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/reshape/pivot.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9waXZvdC5weQ==) | `8.77% <ø> (-87.78%)` | :arrow_down: |
| [pandas/core/reshape/concat.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9jb25jYXQucHk=) | `44% <ø> (-53.2%)` | :arrow_down: |
| [pandas/core/reshape/tile.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS90aWxlLnB5) | `11.04% <ø> (-86.63%)` | :arrow_down: |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `33.33% <ø> (-64.43%)` | :arrow_down: |
| [pandas/core/reshape/reshape.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9yZXNoYXBlLnB5) | `13.36% <ø> (-86%)` | :arrow_down: |
| [pandas/core/arrays/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2NhdGVnb3JpY2FsLnB5) | `41.33% <ø> (-54.65%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `34.55% <ø> (-62.33%)` | :arrow_down: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `65.72% <ø> (-32.08%)` | :arrow_down: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `38.42% <ø> (-55.75%)` | :arrow_down: |
| [pandas/core/strings.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3RyaW5ncy5weQ==) | `33% <ø> (-65.59%)` | :arrow_down: |
| ... and [139 more](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25295?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/25295?src=pr&el=footer). Last update [4d44a2a...293227b](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=h1) Report
> Merging [#25295](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/83fe6ca422ecc35f311897abedadcc492b2a0777?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/25295/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25295   +/-   ##
=======================================
  Coverage   91.72%   91.72%           
=======================================
  Files         173      173           
  Lines       52831    52831           
=======================================
  Hits        48457    48457           
  Misses       4374     4374
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.28% <ø> (ø)` | :arrow_up: |
| #single | `41.72% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/reshape/pivot.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9waXZvdC5weQ==) | `96.55% <ø> (ø)` | :arrow_up: |
| [pandas/core/reshape/concat.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9jb25jYXQucHk=) | `97.2% <ø> (ø)` | :arrow_up: |
| [pandas/core/reshape/tile.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS90aWxlLnB5) | `97.67% <ø> (ø)` | :arrow_up: |
| [pandas/core/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYmFzZS5weQ==) | `97.76% <ø> (ø)` | :arrow_up: |
| [pandas/core/reshape/reshape.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9yZXNoYXBlLnB5) | `99.35% <ø> (ø)` | :arrow_up: |
| [pandas/core/arrays/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2NhdGVnb3JpY2FsLnB5) | `95.97% <ø> (ø)` | :arrow_up: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.87% <ø> (ø)` | :arrow_up: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `97.79% <ø> (ø)` | :arrow_up: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `94.16% <ø> (ø)` | :arrow_up: |
| [pandas/core/strings.py](https://codecov.io/gh/pandas-dev/pandas/pull/25295/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3RyaW5ncy5weQ==) | `98.58% <ø> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25295?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/25295?src=pr&el=footer). Last update [83fe6ca...292b64d](https://codecov.io/gh/pandas-dev/pandas/pull/25295?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Makes sense though for now just keep it limited to the ones already in this PR. Can tackle others in a follow up if required

Sent from my iPhone

> On Feb 16, 2019, at 5:36 AM, Daniel Saxton <notifications@github.com> wrote:
> 
> @dsaxton commented on this pull request.
> 
> In pandas/core/reshape/pivot.py:
> 
> > @@ -467,20 +473,20 @@ def crosstab(index, columns, values=None, rownames=None, colnames=None,
>  
>      >>> foo = pd.Categorical(['a', 'b'], categories=['a', 'b', 'c'])
>      >>> bar = pd.Categorical(['d', 'e'], categories=['d', 'e', 'f'])
> -    >>> crosstab(foo, bar)  # 'c' and 'f' are not represented in the data,
> +    >>> pd.crosstab(foo, bar)  # 'c' and 'f' are not represented in the data,
> +    ... # doctest: +SKIP
> Good idea. I also noticed that the doctest comments are exposed in the documentation:
> 
> https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.crosstab.html
> 
> I removed them for crosstab and the docstring still validates, so maybe worth trying to do this elsewhere as well?
> 
> —
> You are receiving this because you commented.
> Reply to this email directly, view it on GitHub, or mute the thread.
 > Makes sense though for now just keep it limited to the ones already in this PR. Can tackle others in a follow up if required

Maybe @datapythonista has some thoughts on this? lgtm. would be nice to catch more of these validation issues automatically.