DOC: Updated docstrings related to DateTimeIndex. GH22459
- [ ] closes #xxxx
- [x] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Updated `pandas.date_range` and `pandas.bdate_range` docstrings to resolve errors raised from `scripts/validate_docstrings.py` from #22459. Also added an example to `pandas.bdate_range`.
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22504?src=pr&el=h1) Report
> Merging [#22504](https://codecov.io/gh/pandas-dev/pandas/pull/22504?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4f717551b8e49ecd978bb4f5a985d6f6a96d86e9?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22504/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22504?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #22504      +/-   ##
==========================================
+ Coverage   92.22%   92.23%   +<.01%     
==========================================
  Files         161      161              
  Lines       51187    51197      +10     
==========================================
+ Hits        47209    47220      +11     
+ Misses       3978     3977       -1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.61% <ø> (ø)` | :arrow_up: |
| #single | `42.27% <ø> (+0.01%)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/22504?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/datetimes.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9kYXRldGltZXMucHk=) | `96.41% <ø> (ø)` | :arrow_up: |
| [pandas/core/arrays/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3RpbWVkZWx0YXMucHk=) | `93.75% <0%> (-0.56%)` | :arrow_down: |
| [pandas/core/indexes/api.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9hcGkucHk=) | `99% <0%> (ø)` | :arrow_up: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `96.81% <0%> (ø)` | :arrow_up: |
| [pandas/core/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc2VyaWVzLnB5) | `93.87% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy90aW1lZGVsdGFzLnB5) | `90.74% <0%> (+0.12%)` | :arrow_up: |
| [pandas/core/indexes/frozen.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9mcm96ZW4ucHk=) | `92.1% <0%> (+0.43%)` | :arrow_up: |
| [pandas/core/arrays/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/22504/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3BlcmlvZC5weQ==) | `98.08% <0%> (+0.59%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22504?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/22504?src=pr&el=footer). Last update [4f71755...0e825d8](https://codecov.io/gh/pandas-dev/pandas/pull/22504?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @datapythonista  Hello @eldritchideen! Thanks for updating the PR.

 - There are no PEP8 issues in the file [`pandas/core/indexes/datetimes.py`](https://github.com/eldritchideen/pandas/blob/4e048869ec709b0fe02b8c80d611c61328355d90/pandas/core/indexes/datetimes.py) !

 @eldritchideen : Can you rebase onto `master` ?  That will fix the Circle CI failures. @eldritchideen Can you please merge master into your PR? `git fetch upstream && git merge upstream/master && git push`

This will rerun the CI checks, and when everything is green we can merge this. Rebased, merging on green. thanks @eldritchideen 