Make module suggestion avaliable on built-in modules

Feature or enhancement

Proposal:

Add BuiltinImporter.discover to make it:

class BuiltinImporter:
    @staticmethod
    def discover(spec=None):
        if spec is not None: # assume that built-in modules have no submodule
            return
        yield from sys.builtin_module_names

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-146421

從 issue 中描述的 BuiltinImporter.discover 入口開始，檢查內建模組探索的處理方式。完成標準是：無需將子模組視為受支援項目，即可探索內建模組名稱；開始前請檢查連結的 PR gh-146421，因為相關工作可能已經在進行中。