FileFinder takes a class, not an instance (#7085) (#7086)

The FileFinder takes a tuple of (class, arguments) to instantiate for
each time, rather than an existing instance.

Fixes #7085

Author: Spindel

stdlib/importlib/machinery.pyi

@@ -123,10 +123,10 @@ def all_suffixes() -> list[str]: ...
 
 class FileFinder(importlib.abc.PathEntryFinder):
     path: str
-    def __init__(self, path: str, *loader_details: tuple[importlib.abc.Loader, list[str]]) -> None: ...
+    def __init__(self, path: str, *loader_details: tuple[type[importlib.abc.Loader], list[str]]) -> None: ...
     @classmethod
     def path_hook(
-        cls, *loader_details: tuple[importlib.abc.Loader, list[str]]
+        cls, *loader_details: tuple[type[importlib.abc.Loader], list[str]]
     ) -> Callable[[str], importlib.abc.PathEntryFinder]: ...
 
 class SourceFileLoader(importlib.abc.FileLoader, importlib.abc.SourceLoader):  # type: ignore # argument disparities