Follow-up of the issue #26567 which added PyErr_ResourceWarning() (C API), attached patch adds a new source parameter to the warnings.warn() function (Python API).

source is the destroyed object which emits a ResourceWarning. The source is used to show the traceback where the object was created (allocated) when tracemalloc is used.

The patch also changes _pyio, asyncio and asyncore modules to set the source parameter.

Note: tempfile doesn't set source because it uses a class method:

    @classmethod
    def _cleanup(cls, name, warn_message):
        _shutil.rmtree(name)
        _warnings.warn(warn_message, ResourceWarning)