Missing Windows step for installing coverage

In /coverage/ section 5.2.1.1
When installing coverage on Windows, the second command step can not be used:

source ../cpython-venv/bin/activate

Instead, there should probably be some mention of the proper step:

..\cpython-venv\Scripts\activate.bat

Which allows you to enter the virtual environment and continue with the instructions.

從 /coverage/ 文件的第 5.2.1.1 節開始，將現有的虛擬環境啟用命令與 issue 中提供的 Windows 專用命令進行比較。更新說明以提及 Windows 啟用步驟，然後確認相關的安裝流程對 Windows 讀者而言仍然清楚。