[Feature] Pytest - Rename @allure.testcase decorator to @allure.tms

[//]: # (
. Note: for support questions, please use Stackoverflow or Gitter**.
. This repository's issues are reserved for feature requests and bug reports.
.
. In case of any problems with Allure Jenkins plugin** please use the following repository
. to create an issue: https://github.com/jenkinsci/allure-plugin/issues
.
. Make sure you have a clear name for your issue. The name should start with a capital
. letter and no dot is required in the end of the sentence. An example of good issue names:
.
. - The report is broken in IE11
. - Add an ability to disable default plugins
. - Support emoji in test descriptions
)

#### I'm submitting a ...
- [ ] bug report
- [x] feature request
- [ ] support request => Please do not submit support request here, see note at the top of this template.

#### What is the current behavior?
The different Allure API implementations use different names for the testcase link:

- Python behave: `@allure.tms:TMS-456`
- Python pytest: `@allure.testcase("TMS-456")`
- Java JUnit: `@TmsLink("TMS-456")`
- .Net NUnit: `[AllureTms("TMS-456")]`
- Cucumber.js: `this.tms("https://example.com/tms/TMS-456", "TMS-456");`
- PHPUnit: `#[TmsLink('TMS-456')]`

#### What is the expected behavior?
For the sake of coherence, could we rename the `@allure.testcase` decorator to `@allure.tms` for pytest ?

#### What is the motivation / use case for changing the behavior?
To have a coherent API

#### Please tell us about your environment:

- Allure version: 2.25.0
- Test framework: pytest@7.4.2
- Allure adaptor: allure-pytest@2.13.2

#### Other information

[//]: # (
. e.g. detailed explanation, stacktraces, related issues, suggestions
. how to fix, links for us to have more context, eg. Stackoverflow, Gitter etc
)

まず、デコレーター @allure.testcase に対応する pytest アダプターのエントリーポイントと、それを扱っているテストやドキュメントを見つけます。提案されている @allure.tms という名前が既存の API と併用された場合にどのように動作すべきかを確認し、そのうえで pytest ユーザーが一貫性のあるデコレーター名を使って同じ TMS-456 リンクを作成できることを検証します。

索引モデルが issue の本文から書いたものです。