DOC: infer_objects doc fixup
follow up to #16915
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=h1) Report
> Merging [#17018](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e5de21a991408b3d3783489989201826af8ada67?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/17018/graphs/tree.svg?src=pr&width=650&token=eZ4WkYLtcO&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17018      +/-   ##
==========================================
- Coverage   91.02%      91%   -0.02%     
==========================================
  Files         161      161              
  Lines       49298    49298              
==========================================
- Hits        44873    44864       -9     
- Misses       4425     4434       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.77% <ø> (ø)` | :arrow_up: |
| #single | `40.18% <ø> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `92.31% <ø> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.76% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17018?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/17018?src=pr&el=footer). Last update [e5de21a...7f92267](https://codecov.io/gh/pandas-dev/pandas/pull/17018?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/17018?src=pr&el=h1) Report
> Merging [#17018](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e5de21a991408b3d3783489989201826af8ada67?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/17018/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #17018      +/-   ##
==========================================
- Coverage   91.02%      91%   -0.02%     
==========================================
  Files         161      161              
  Lines       49298    49298              
==========================================
- Hits        44873    44864       -9     
- Misses       4425     4434       +9
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.77% <ø> (ø)` | :arrow_up: |
| #single | `40.18% <ø> (-0.07%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `92.31% <ø> (ø)` | :arrow_up: |
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.76% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/17018?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/17018?src=pr&el=footer). Last update [e5de21a...7f92267](https://codecov.io/gh/pandas-dev/pandas/pull/17018?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks!