Broken Return type link for service_context

On the SDK page for Workspace Class [here](https://docs.microsoft.com/en-us/python/api/azureml-core/azureml.core.workspace.workspace?view=azure-ml-py), the return type for **service_context** renders as `` rather than as a link to the ServiceContext class documentation.

(N.B. This seems like the wrong issues list to add this to, but it is the one linked to by *View all page feedback* at the bottom of [the page](https://docs.microsoft.com/en-us/python/api/azureml-core/azureml.core.workspace.workspace?view=azure-ml-py).)

開啟連結的 Workspace Class SDK 頁面並檢查 service_context 回傳型別。檢查在產生的文件中如何參照 ServiceContext 類別；當回傳型別呈現為指向該類別的可點選連結，而不是原始 xref 文字時，即表示完成。

由索引模型根據 Issue 內容生成。