saveFinish
Finishes a file saving started with method@FileSaver.save_async.
If the file has been saved successfully, the following class@File properties will be updated: the location, the encoding, the newline type and the compression type.
Since the 3.20 version, method@Gtk.TextBuffer.set_modified is called with false if the file has been saved successfully.
Return
whether the file was saved successfully.
Parameters
result
a #GAsyncResult.