Improvements to Lifecycle of a pull request

I write this issue as a feedback from Euro Python 2024 sprint to denote troubles I encountered as I contributed to cpython.

Describe the enhancement or feature you'd like
Missing content in "Lifecycle of a pull request" https://devguide.python.org/getting-started/pull-request-lifecycle/

• "Quick guide" is missing a step to create NEWS.d record. It's just very briefly mentioned in patchcheck.
• "Step-by-step guide" doesn't denote a branch naming convention. I was told to use gh-<number>-<name>.
• "Making good commits" doesn't mention gh-<number> should be included in the commit message.
• "Step-by-step guide" doesn't mention gh-<number> should be included in the PR title.

Describe alternatives you've considered
None.

從 Python developer’s guide 中連結的「Lifecycle of a pull request」頁面開始，查看其中的 Quick guide、Step-by-step guide 和 Making good commits 部分。更新文件，涵蓋 NEWS.d record 以及 gh- 的命名和訊息慣例；當所有四項要求的 workflow 詳細資訊都已明確說明時，即表示完成。