delete-auto-save-files is a variable defined in ‘files.el’.
Its value is t
Documentation:
Non-nil means delete auto-save file when a buffer is saved or killed.
Note that the auto-save file will not be deleted if the buffer is killed
when it has unsaved changes.
If you want auto-saving to be done in the visited file rather than
in a separate auto-save file, enable the global minor mode
`auto-save-visited-mode’. In this mode, auto-saving is identical to
explicit saving.