DOC: Improvement docstring of DataFrame.rank()
- [X] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

I have made the changes requested in the pull request #23263 

This is the output of the docstring validation:
```
3 Errors found:
	Parameter "method" description should finish with "."
	Parameter "na_option" description should finish with "."
	The first line of the Returns section should contain only the type, unless multiple values are being returned
```
In the previous pull request I have been told that I could ignore these 3 errors.

Please let me know if I can further improve the docstring.

Thanks a lot
# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=h1) Report
> Merging [#25328](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4be995c13452766da48a82f3ecd0b5a24e48f526?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/25328/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #25328   +/-   ##
=======================================
  Coverage   91.72%   91.72%           
=======================================
  Files         173      173           
  Lines       52831    52831           
=======================================
  Hits        48458    48458           
  Misses       4373     4373
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.28% <ø> (ø)` | :arrow_up: |
| #single | `41.72% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `94.16% <ø> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25328?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/25328?src=pr&el=footer). Last update [4be995c...9fbe884](https://codecov.io/gh/pandas-dev/pandas/pull/25328?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/25328?src=pr&el=h1) Report
> Merging [#25328](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/4be995c13452766da48a82f3ecd0b5a24e48f526?src=pr&el=desc) will **increase** coverage by `0.25%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/25328/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #25328      +/-   ##
==========================================
+ Coverage   91.72%   91.98%   +0.26%     
==========================================
  Files         173      175       +2     
  Lines       52831    52374     -457     
==========================================
- Hits        48458    48175     -283     
+ Misses       4373     4199     -174
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.53% <100%> (+0.25%)` | :arrow_up: |
| #single | `40.71% <12.5%> (-1.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `93.54% <100%> (-0.63%)` | :arrow_down: |
| [pandas/core/panel.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcGFuZWwucHk=) | `35.43% <0%> (-36.32%)` | :arrow_down: |
| [pandas/io/clipboard/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2NsaXBib2FyZC9fX2luaXRfXy5weQ==) | `39.21% <0%> (-17.65%)` | :arrow_down: |
| [pandas/util/\_doctools.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvX2RvY3Rvb2xzLnB5) | `0% <0%> (-12.88%)` | :arrow_down: |
| [pandas/io/clipboard/clipboards.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2NsaXBib2FyZC9jbGlwYm9hcmRzLnB5) | `18.98% <0%> (-11.61%)` | :arrow_down: |
| [pandas/io/formats/console.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvY29uc29sZS5weQ==) | `78.12% <0%> (-8.15%)` | :arrow_down: |
| [pandas/plotting/\_compat.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb21wYXQucHk=) | `83.33% <0%> (-4.17%)` | :arrow_down: |
| [pandas/core/config\_init.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY29uZmlnX2luaXQucHk=) | `96.96% <0%> (-2.28%)` | :arrow_down: |
| [pandas/core/sparse/series.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvc3BhcnNlL3Nlcmllcy5weQ==) | `93.3% <0%> (-2.24%)` | :arrow_down: |
| [pandas/core/indexing.py](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhpbmcucHk=) | `90.53% <0%> (-1.74%)` | :arrow_down: |
| ... and [135 more](https://codecov.io/gh/pandas-dev/pandas/pull/25328/diff?src=pr&el=tree-more) | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/25328?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/25328?src=pr&el=footer). Last update [4be995c...7de320e](https://codecov.io/gh/pandas-dev/pandas/pull/25328?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 lgtm. @WillAyd over to you. @EdAbati can you merge master and address comments above? Should be simple fixes Hi @WillAyd ,

I have solved the docstring validation errors above.

Please let me know if I should make any changes.

Thanks  @EdAbati can you address previous comment and merge master? Hi @WillAyd,

I could not find a nice description for the parameters of this method without using bullet points.
So I have tried to fix the validation script as highlighted in the issue #25461
I am about to raise a PR for this.

If the PR is accepted, I was planning to only remove the bullet points at the end of each bullet. 

Edit : I have just created a PR #25786 can you merge master @EdAbati can you merge master? Don't think we need to wait on your other PR to get this one through Hi @WillAyd ,

Apologies for the delay, I have been away and very busy lately. I have just removed the bullet points in the 2 parameter lists.

I will soon update the other PR as well. @EdAbati sorry for having taken so long on my end. This is a nice update - great job for a first contribution!