BUG: Hashtable size hint cap
- [x] closes #22729
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Hello @chris-b1! Thanks for updating the PR.

 - In the file [`pandas/tests/test_algos.py`](https://github.com/pandas-dev/pandas/blob/d3cbb2bf64016f4cd8a719f10dfd1e1459e4f690/pandas/tests/test_algos.py), following are the PEP8 issues :

> [Line 1419:45](https://github.com/pandas-dev/pandas/blob/d3cbb2bf64016f4cd8a719f10dfd1e1459e4f690/pandas/tests/test_algos.py#L1419): [E261](https://duckduckgo.com/?q=pep8%20E261) at least two spaces before inline comment



##### Comment last updated on January 14, 2019 at 20:09 Hours UTC can you rebase @chris-b1 can you rebase / update # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=h1) Report
> Merging [#22805](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/9bc42f9d296cf717533051ee76130e72ea9ce557?src=pr&el=desc) will **decrease** coverage by `0.03%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22805/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22805      +/-   ##
==========================================
- Coverage   92.21%   92.18%   -0.04%     
==========================================
  Files         162      169       +7     
  Lines       51768    50810     -958     
==========================================
- Hits        47739    46839     -900     
+ Misses       4029     3971      -58
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.6% <ø> (-0.02%)` | :arrow_down: |
| #single | `42.37% <ø> (-0.63%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/formats/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvaHRtbC5weQ==) | `90.68% <0%> (-7.93%)` | :arrow_down: |
| [pandas/core/arrays/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3BlcmlvZC5weQ==) | `91.98% <0%> (-6.31%)` | :arrow_down: |
| [pandas/plotting/\_tools.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL190b29scy5weQ==) | `72.62% <0%> (-6.15%)` | :arrow_down: |
| [pandas/io/feather\_format.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2ZlYXRoZXJfZm9ybWF0LnB5) | `85.71% <0%> (-4.03%)` | :arrow_down: |
| [pandas/io/parquet.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3BhcnF1ZXQucHk=) | `73.72% <0%> (-3.2%)` | :arrow_down: |
| [pandas/core/arrays/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2Jhc2UucHk=) | `94.24% <0%> (-3.18%)` | :arrow_down: |
| [pandas/plotting/\_style.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19zdHlsZS5weQ==) | `74.28% <0%> (-3.14%)` | :arrow_down: |
| [pandas/core/sparse/scipy\_sparse.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3BhcnNlL3NjaXB5X3NwYXJzZS5weQ==) | `97.05% <0%> (-2.95%)` | :arrow_down: |
| [pandas/core/arrays/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2RhdGV0aW1lcy5weQ==) | `96.82% <0%> (-1.74%)` | :arrow_down: |
| [pandas/core/indexes/range.py](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9yYW5nZS5weQ==) | `95.73% <0%> (-1.6%)` | :arrow_down: |
| ... and [136 more](https://codecov.io/gh/pandas-dev/pandas/pull/22805/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22805?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/22805?src=pr&el=footer). Last update [9bc42f9...74b3b45](https://codecov.io/gh/pandas-dev/pandas/pull/22805?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/22805?src=pr&el=h1) Report
> Merging [#22805](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/ff40c2f74abecd3e898eae79274b24b4745eaa0e?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22805/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #22805   +/-   ##
=======================================
  Coverage   92.38%   92.38%           
=======================================
  Files         166      166           
  Lines       52363    52363           
=======================================
  Hits        48377    48377           
  Misses       3986     3986
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.81% <ø> (ø)` | :arrow_up: |
| #single | `42.91% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22805?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/22805?src=pr&el=footer). Last update [ff40c2f...d3cbb2b](https://codecov.io/gh/pandas-dev/pandas/pull/22805?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @jreback - I think this is good now This just needs a rebase and it looks good to go (Travis failure was a timeout) can you merge master and update @chris-b1 can you merge master @jreback - should be good now! thanks @chris-b1 