Implement reductions from #24024
min/max signatures+docstrings are changed from #24024, instead match those of DatetimeIndexOpsMixin (with appropriate docstring edits)

The min/max implementations are unchanged from 24024.  In an upcoming pass I'll see if we can pawn any more of it off to nanops.

Tests are verbatim from 24024.
ping on green. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=h1) Report
> Merging [#24484](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/41b2b18b94ade34a172483cf8307ce16bbbfc7c1?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `96.15%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24484/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24484      +/-   ##
==========================================
+ Coverage    92.3%   92.31%   +<.01%     
==========================================
  Files         166      166              
  Lines       52386    52412      +26     
==========================================
+ Hits        48357    48382      +25     
- Misses       4029     4030       +1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.73% <96.15%> (ø)` | :arrow_up: |
| #single | `43.05% <15.38%> (-0.02%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/arrays/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lbGlrZS5weQ==) | `95.5% <96.15%> (+0.03%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24484?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/24484?src=pr&el=footer). Last update [41b2b18...bf99607](https://codecov.io/gh/pandas-dev/pandas/pull/24484?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/24484?src=pr&el=h1) Report
> Merging [#24484](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/aeff38d3301d4d31650f6624304259d0dfdbd69b?src=pr&el=desc) will **decrease** coverage by `49.27%`.
> The diff coverage is `15.38%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24484/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=tree)

```diff
@@             Coverage Diff             @@
##           master   #24484       +/-   ##
===========================================
- Coverage   92.31%   43.03%   -49.28%     
===========================================
  Files         166      166               
  Lines       52335    52361       +26     
===========================================
- Hits        48313    22535    -25778     
- Misses       4022    29826    +25804
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `?` | |
| #single | `43.03% <15.38%> (-0.02%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/arrays/datetimelike.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lbGlrZS5weQ==) | `44.6% <15.38%> (-51.06%)` | :arrow_down: |
| [pandas/io/formats/latex.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvbGF0ZXgucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/core/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY2F0ZWdvcmljYWwucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/io/sas/sas\_constants.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXNfY29uc3RhbnRzLnB5) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/tseries/plotting.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvcGxvdHRpbmcucHk=) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/tseries/converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvY29udmVydGVyLnB5) | `0% <0%> (-100%)` | :arrow_down: |
| [pandas/io/formats/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvaHRtbC5weQ==) | `0% <0%> (-98.65%)` | :arrow_down: |
| [pandas/core/groupby/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS9jYXRlZ29yaWNhbC5weQ==) | `0% <0%> (-95.46%)` | :arrow_down: |
| [pandas/io/sas/sas7bdat.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXM3YmRhdC5weQ==) | `0% <0%> (-91.17%)` | :arrow_down: |
| [pandas/io/sas/sas\_xport.py](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3Nhcy9zYXNfeHBvcnQucHk=) | `0% <0%> (-90.15%)` | :arrow_down: |
| ... and [125 more](https://codecov.io/gh/pandas-dev/pandas/pull/24484/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24484?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/24484?src=pr&el=footer). Last update [aeff38d...244d37b](https://codecov.io/gh/pandas-dev/pandas/pull/24484?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 this will need rebase following #24476. Ping