Small cleanups
Broken off from another branch to trim the diff on an upcoming PR.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=h1) Report
> Merging [#26874](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/430f0fd04646a0ab44ccbfbad706dfe22e9fabfe?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26874/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26874      +/-   ##
==========================================
- Coverage   91.88%   91.87%   -0.02%     
==========================================
  Files         179      179              
  Lines       50696    50693       -3     
==========================================
- Hits        46581    46573       -8     
- Misses       4115     4120       +5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.46% <100%> (-0.01%)` | :arrow_down: |
| #single | `41.09% <75%> (-0.08%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/arrays/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lbGlrZS5weQ==) | `97.92% <ø> (-0.01%)` | :arrow_down: |
| [pandas/core/dtypes/concat.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2NvbmNhdC5weQ==) | `96.58% <ø> (ø)` | :arrow_up: |
| [pandas/core/internals/managers.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL21hbmFnZXJzLnB5) | `95.21% <ø> (-0.01%)` | :arrow_down: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `97.79% <ø> (-0.01%)` | :arrow_down: |
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.91% <100%> (ø)` | :arrow_up: |
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `94.38% <100%> (-0.01%)` | :arrow_down: |
| [pandas/core/internals/construction.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2NvbnN0cnVjdGlvbi5weQ==) | `95.93% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.88% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.84% <0%> (-0.11%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26874?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/26874?src=pr&el=footer). Last update [430f0fd...e854fa2](https://codecov.io/gh/pandas-dev/pandas/pull/26874?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/26874?src=pr&el=h1) Report
> Merging [#26874](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/430f0fd04646a0ab44ccbfbad706dfe22e9fabfe?src=pr&el=desc) will **decrease** coverage by `0.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26874/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26874      +/-   ##
==========================================
- Coverage   91.88%   91.87%   -0.02%     
==========================================
  Files         179      179              
  Lines       50696    50693       -3     
==========================================
- Hits        46581    46573       -8     
- Misses       4115     4120       +5
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.46% <100%> (-0.01%)` | :arrow_down: |
| #single | `41.09% <75%> (-0.08%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/arrays/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lbGlrZS5weQ==) | `97.92% <ø> (-0.01%)` | :arrow_down: |
| [pandas/core/dtypes/concat.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2NvbmNhdC5weQ==) | `96.58% <ø> (ø)` | :arrow_up: |
| [pandas/core/internals/managers.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL21hbmFnZXJzLnB5) | `95.21% <ø> (-0.01%)` | :arrow_down: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `97.79% <ø> (-0.01%)` | :arrow_down: |
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `97.91% <100%> (ø)` | :arrow_up: |
| [pandas/core/internals/blocks.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2Jsb2Nrcy5weQ==) | `94.38% <100%> (-0.01%)` | :arrow_down: |
| [pandas/core/internals/construction.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW50ZXJuYWxzL2NvbnN0cnVjdGlvbi5weQ==) | `95.93% <100%> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `88.88% <0%> (-11.12%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.88% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26874/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.84% <0%> (-0.11%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26874?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/26874?src=pr&el=footer). Last update [430f0fd...e854fa2](https://codecov.io/gh/pandas-dev/pandas/pull/26874?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
