Fix some of the typing for CFFI's out of line mode (#14090)

Author: A5rocks

stubs/cffi/_cffi_backend.pyi

@@ -127,7 +127,7 @@ class FFI:
 
     def __init__(
         self,
-        module_name: bytes = ...,
+        module_name: str = ...,
         _version: int = ...,
         _types: bytes = ...,
         _globals: tuple[bytes | int, ...] = ...,
@@ -157,7 +157,7 @@ class FFI:
         error: Any = ...,
         onerror: Callable[[Exception, Any, Any], None] | None = ...,
     ) -> Callable[..., _T]: ...
-    def cast(self, cdecl: str | CType, value: CData) -> CData: ...
+    def cast(self, cdecl: str | CType, value: CData | int) -> CData: ...
     def def_extern(
         self, name: str = ..., error: Any = ..., onerror: Callable[[Exception, Any, types.TracebackType], Any] = ...
     ) -> Callable[[Callable[..., _T]], Callable[..., _T]]: ...

stubs/cffi/cffi/api.pyi

@@ -89,7 +89,7 @@ class FFI:
     def from_handle(self, x: CData) -> Any: ...
     def release(self, x: CData) -> None: ...
     def set_unicode(self, enabled_flag: bool) -> None: ...
-    def set_source(self, module_name: str, source: str, source_extension: str = ".c", **kwds: Any) -> None: ...
+    def set_source(self, module_name: str, source: str | None, source_extension: str = ".c", **kwds: Any) -> None: ...
     def set_source_pkgconfig(
         self, module_name: str, pkgconfig_libs: list[str], source: str, source_extension: str = ".c", **kwds: Any
     ) -> None: ...