[DOC] Fix issues with DataFrame.aggregate page
Fixed some formatting issues. Description was gettign rendered in the
wrong location.

Moved a line from generic.py to frame.py to help with the rendering.
Moved the description being clubbed with see also to doc string with the
function declaration in frame.py

- closes #24668

-  passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

Hello @rotuna! Thanks for updating the PR.













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

##### Comment last updated on January 27, 2019 at 04:48 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=h1) Report
> Merging [#24948](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/9561b9621fd41735b59c48a61a860b4ec9a3a1a3?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24948/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24948      +/-   ##
==========================================
+ Coverage   91.73%   91.73%   +<.01%     
==========================================
  Files         173      173              
  Lines       52838    52839       +1     
==========================================
+ Hits        48471    48473       +2     
+ Misses       4367     4366       -1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.29% <100%> (ø)` | :arrow_up: |
| #single | `41.71% <100%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `94.16% <ø> (ø)` | :arrow_up: |
| [pandas/core/groupby/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9nZW5lcmljLnB5) | `86.98% <100%> (ø)` | :arrow_up: |
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `93.7% <100%> (ø)` | :arrow_up: |
| [pandas/core/window.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvd2luZG93LnB5) | `96.4% <100%> (ø)` | :arrow_up: |
| [pandas/core/resample.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzYW1wbGUucHk=) | `97.22% <100%> (ø)` | :arrow_up: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.87% <100%> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `87.66% <0%> (+0.09%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24948?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/24948?src=pr&el=footer). Last update [9561b96...ecb2e45](https://codecov.io/gh/pandas-dev/pandas/pull/24948?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/24948?src=pr&el=h1) Report
> Merging [#24948](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/2626215ca5dd168ea311f117b988693cef437885?src=pr&el=desc) will **decrease** coverage by `49.47%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24948/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=tree)

```diff
@@             Coverage Diff             @@
##           master   #24948       +/-   ##
===========================================
- Coverage   92.37%    42.9%   -49.48%     
===========================================
  Files         166      166               
  Lines       52388    52388               
===========================================
- Hits        48396    22475    -25921     
- Misses       3992    29913    +25921
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `?` | |
| #single | `42.9% <100%> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `39.86% <ø> (-56.77%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `35.84% <100%> (-61.08%)` | :arrow_down: |
| [pandas/io/formats/latex.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvbGF0ZXgucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/core/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY2F0ZWdvcmljYWwucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/io/sas/sas\_constants.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXNfY29uc3RhbnRzLnB5) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/tseries/plotting.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvcGxvdHRpbmcucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/tseries/converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvY29udmVydGVyLnB5) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/io/formats/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvaHRtbC5weQ==) | `0% <0%> (-99.35%)` | :arrow_down: |
| [pandas/core/groupby/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9jYXRlZ29yaWNhbC5weQ==) | `0% <0%> (-95.46%)` | :arrow_down: |
| [pandas/io/sas/sas7bdat.py](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXM3YmRhdC5weQ==) | `0% <0%> (-91.17%)` | :arrow_down: |
| ... and [125 more](https://codecov.io/gh/pandas-dev/pandas/pull/24948/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24948?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/24948?src=pr&el=footer). Last update [2626215...9fc48fa](https://codecov.io/gh/pandas-dev/pandas/pull/24948?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @rotuna any chance you could post the output of `scripts/validate_docstrings.py` for the items you are changing? Would be helpful to see how these ultimately render Sure Hi, 

@WillAyd 

I've attached the output for all the aggregate pages. I can attach the rendered HTML too if you want.

The zip of the output files is here: 
[Archive.zip](https://github.com/pandas-dev/pandas/files/2812118/Archive.zip)

Rendered HTML files are here: 
[html.zip](https://github.com/pandas-dev/pandas/files/2812428/html.zip)

 @WillAyd Do I need to make any further changes? Sorry missed previous ping - can you merge master and resolve conflicts? Will take a look after that @rotuna can you merge master? @rotuna looks like there's a merge conflict. Can you merge master & push the update? @rotuna can you merge master and resolve the conflict here? Closing as stale. Ping if you'd like to pick this back up