[pydoc] safeimport can return None (#9856)

Author: Károly Szabó

stdlib/pydoc.pyi

@@ -40,7 +40,7 @@ class ErrorDuringImport(Exception):
     def __init__(self, filename: str, exc_info: OptExcInfo) -> None: ...
 
 def importfile(path: str) -> ModuleType: ...
-def safeimport(path: str, forceload: bool = ..., cache: MutableMapping[str, ModuleType] = ...) -> ModuleType: ...
+def safeimport(path: str, forceload: bool = ..., cache: MutableMapping[str, ModuleType] = ...) -> ModuleType | None: ...
 
 class Doc:
     PYTHONDOCS: str