DEPR: Deprecating .clip_lower and .clip_upper
- [X] xref #18262
- [X] tests added / passed
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [X] whatsnew entry

Hello @datapythonista! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/core/generic.py`](https://github.com/datapythonista/pandas/blob/b09a0ce143451dcb48aa3a708e00890dd26da9a6/pandas/core/generic.py) !

 - There are no PEP8 issues in the file [`pandas/tests/frame/test_analytics.py`](https://github.com/datapythonista/pandas/blob/b09a0ce143451dcb48aa3a708e00890dd26da9a6/pandas/tests/frame/test_analytics.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_analytics.py`](https://github.com/datapythonista/pandas/blob/b09a0ce143451dcb48aa3a708e00890dd26da9a6/pandas/tests/series/test_analytics.py) !

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=h1) Report
> Merging [#24203](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/138a59a9a06c5f0c31bb853113f7dea90b5a556d?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24203/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24203      +/-   ##
==========================================
- Coverage   92.21%   92.21%   -0.01%     
==========================================
  Files         162      162              
  Lines       51723    51725       +2     
==========================================
+ Hits        47695    47696       +1     
- Misses       4028     4029       +1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.61% <100%> (ø)` | :arrow_up: |
| #single | `43.03% <0%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/24203/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `96.65% <100%> (ø)` | :arrow_up: |
| [pandas/io/json/json.py](https://codecov.io/gh/pandas-dev/pandas/pull/24203/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2pzb24vanNvbi5weQ==) | `92.61% <0%> (-0.48%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24203/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `87.51% <0%> (+0.09%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24203?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/24203?src=pr&el=footer). Last update [138a59a...5d0d01a](https://codecov.io/gh/pandas-dev/pandas/pull/24203?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/24203?src=pr&el=h1) Report
> Merging [#24203](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/53899874f8c33bf00b68d270beee2640078f3cd6?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/24203/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24203      +/-   ##
==========================================
+ Coverage   92.21%   92.21%   +<.01%     
==========================================
  Files         162      162              
  Lines       51761    51763       +2     
==========================================
+ Hits        47731    47733       +2     
  Misses       4030     4030
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.61% <100%> (ø)` | :arrow_up: |
| #single | `43% <0%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/24203/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `96.65% <100%> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24203?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/24203?src=pr&el=footer). Last update [5389987...383f6d6](https://codecov.io/gh/pandas-dev/pandas/pull/24203?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 and pls merge master lgtm. merge on green.