Fix docstring templates not being filled (#24535)
State: closed

- [x] closes #24535
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Fixes the docstring template issue


Labels:
name: Bug
name: Docs

Comments:
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=h1) Report
> Merging [#24584](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/268150f191884a554359de512ad6330977501796?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24584/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24584      +/-   ##
==========================================
- Coverage   92.36%   92.36%   -0.01%     
==========================================
  Files         166      166              
  Lines       52497    52497              
==========================================
- Hits        48490    48489       -1     
- Misses       4007     4008       +1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.79% <ø> (ø)` | :arrow_up: |
| #single | `43.04% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/24584/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `96.29% <ø> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24584/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `88% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24584?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/24584?src=pr&el=footer). Last update [268150f...68e0cf5](https://codecov.io/gh/pandas-dev/pandas/pull/24584?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/24584?src=pr&el=h1) Report
> Merging [#24584](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/268150f191884a554359de512ad6330977501796?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24584/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24584      +/-   ##
==========================================
- Coverage   92.36%   92.36%   -0.01%     
==========================================
  Files         166      166              
  Lines       52497    52497              
==========================================
- Hits        48490    48489       -1     
- Misses       4007     4008       +1
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.79% <ø> (ø)` | :arrow_up: |
| #single | `43.04% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/indexes/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/24584/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9iYXNlLnB5) | `96.29% <ø> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24584/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `88% <0%> (-0.1%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24584?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/24584?src=pr&el=footer). Last update [268150f...68e0cf5](https://codecov.io/gh/pandas-dev/pandas/pull/24584?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).

thanks