MAINT: Standardize searchsorted signature
"value" is the law of the land.

xref #14645.

Follow-up to #15601.
Hello @gfyoung! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/core/indexes/frozen.py`](https://github.com/gfyoung/pandas/blob/8d1b41d09e8f2ab86fbebcdaa3eaffa51c16d0b5/pandas/core/indexes/frozen.py) !

 - There are no PEP8 issues in the file [`pandas/tests/indexes/test_frozen.py`](https://github.com/gfyoung/pandas/blob/8d1b41d09e8f2ab86fbebcdaa3eaffa51c16d0b5/pandas/tests/indexes/test_frozen.py) !

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22672?src=pr&el=h1) Report
> Merging [#22672](https://codecov.io/gh/pandas-dev/pandas/pull/22672?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/c04035360a179e82fc534cb4f38979615c53191f?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/22672/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22672?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22672      +/-   ##
==========================================
- Coverage   92.17%   92.17%   -0.01%     
==========================================
  Files         169      169              
  Lines       50715    50710       -5     
==========================================
- Hits        46747    46742       -5     
  Misses       3968     3968
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.58% <100%> (-0.01%)` | :arrow_down: |
| #single | `42.35% <75%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22672?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/frozen.py](https://codecov.io/gh/pandas-dev/pandas/pull/22672/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9mcm96ZW4ucHk=) | `91.42% <100%> (+0.25%)` | :arrow_up: |
| [pandas/core/common.py](https://codecov.io/gh/pandas-dev/pandas/pull/22672/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29tbW9uLnB5) | `97.34% <0%> (-0.06%)` | :arrow_down: |
| [pandas/io/formats/style.py](https://codecov.io/gh/pandas-dev/pandas/pull/22672/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvc3R5bGUucHk=) | `96.42% <0%> (-0.01%)` | :arrow_down: |
| [pandas/core/indexes/multi.py](https://codecov.io/gh/pandas-dev/pandas/pull/22672/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9tdWx0aS5weQ==) | `95.41% <0%> (-0.01%)` | :arrow_down: |
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/22672/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `96.45% <0%> (-0.01%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22672?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/22672?src=pr&el=footer). Last update [c040353...c162b3b](https://codecov.io/gh/pandas-dev/pandas/pull/22672?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 If it isn't part of the public API, then I'd say so.

On Wed, Sep 12, 2018 at 1:23 PM gfyoung <notifications@github.com> wrote:

> *@gfyoung* commented on this pull request.
> ------------------------------
>
> In doc/source/whatsnew/v0.24.0.txt
> <https://github.com/pandas-dev/pandas/pull/22672#discussion_r217139603>:
>
> > @@ -557,6 +557,7 @@ Deprecations
>  - :func:`pandas.read_table` is deprecated. Instead, use :func:`pandas.read_csv` passing ``sep='\t'`` if necessary (:issue:`21948`)
>  - :meth:`Series.str.cat` has deprecated using arbitrary list-likes *within* list-likes. A list-like container may still contain
>    many ``Series``, ``Index`` or 1-dimensional ``np.ndarray``, or alternatively, only scalar values. (:issue:`21950`)
> +- :meth:`FrozenNDArray.searchsorted` has deprecated the ``v`` parameter in favor of ``value`` (:issue:`14645`)
>
> Hmmm...good point. it's not part of the public API. Could we just change
> it immediately?
>
> —
> You are receiving this because you commented.
> Reply to this email directly, view it on GitHub
> <https://github.com/pandas-dev/pandas/pull/22672#discussion_r217139603>,
> or mute the thread
> <https://github.com/notifications/unsubscribe-auth/ABQHIhBfY8IU6Bqh5X29Y2ZVg9GAe5TTks5uaVEPgaJpZM4WkcMY>
> .
>
 @TomAugspurger : Change was made, and everything is still green.  PTAL. Hmm, so I looked at where this was actually used

```python
In [21]: idx = pd.MultiIndex.from_product([['a', 'b'], [1, 2, 3]])

In [22]: idx.labels[0]
Out[22]: FrozenNDArray([0, 0, 0, 1, 1, 1], dtype='int8')
```

which is, I suppose is close enough to public API that this should be deprecated. Sorry about the misleading comment earlier @gfyoung. lgtm @jreback @TomAugspurger : Reverted back to deprecation warning.  If no objections, will merge. ok, pls make sure to add to the deprecations page, otherwise lgtm.