Accept `types.ModuleType` as a distribution identifier

I have recently ran into the issue where the importable module did not come from the distribution metadata found by importlib.metadata. This was because the distribution modules were shadowed in sys.path, which can happen often in test environments.

It would be nice if we could pass a module to importlib.metadata.distribution(), and have it find the distribution where that module originates from, if any.

從 importlib.metadata.distribution() 進入點開始，檢查 distribution 識別碼如何解析，特別注意 types.ModuleType 以及 sys.path 中被遮蔽的模組。確定傳入模組時應如何找到其來源 distribution，包括沒有 distribution 的情況。當模組可以作為識別碼被接受，且針對被遮蔽模組的行為已由測試涵蓋時，即表示完成。