CLN: Remove "flake8: noqa" from files
Just some minor house-cleaning to cut down on the number of search results found <a href="https://github.com/pandas-dev/pandas/search?utf8=%E2%9C%93&q=flake8%3A+noqa&type=">here</a>.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=h1) Report
> Merging [#15842](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/de589c23e0ae79d9cae59674259dc2707513795f?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/15842/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #15842      +/-   ##
==========================================
- Coverage   90.97%   90.96%   -0.02%     
==========================================
  Files         143      143              
  Lines       49442    49442              
==========================================
- Hits        44982    44973       -9     
- Misses       4460     4469       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.72% <ø> (ø)` | :arrow_up: |
| #single | `40.69% <ø> (-0.11%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/util/clipboard/exceptions.py](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvY2xpcGJvYXJkL2V4Y2VwdGlvbnMucHk=) | `71.42% <ø> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.56% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/15842?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/15842?src=pr&el=footer). Last update [de589c2...5d1edeb](https://codecov.io/gh/pandas-dev/pandas/pull/15842?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments). thanks!