DOC: Extension whatsenw
Closes https://github.com/pandas-dev/pandas/issues/20532
Whoops, looks like I branched off the wrong branch. Oh well, fixing some other warnings too I guess :) # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20533?src=pr&el=h1) Report
> Merging [#20533](https://codecov.io/gh/pandas-dev/pandas/pull/20533?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/93bc32b156780aadcb953f91408d90f7e97c72c0?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/20533/graphs/tree.svg?token=eZ4WkYLtcO&width=650&src=pr&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/20533?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #20533      +/-   ##
==========================================
+ Coverage   91.81%   91.84%   +0.02%     
==========================================
  Files         152      152              
  Lines       49259    49259              
==========================================
+ Hits        45229    45241      +12     
+ Misses       4030     4018      -12
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.23% <ø> (+0.02%)` | :arrow_up: |
| #single | `41.89% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20533?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/20533/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `93.85% <ø> (ø)` | :arrow_up: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/20533/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/20533?src=pr&el=continue).
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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
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