lisp/so-long.el: Use (interactive "@") for menu commands

lisp/so-long.el: Use (interactive "@") for menu commands

* lisp/so-long.el (so-long-menu, so-long-menu-item-replace-action)
(so-long-revert): Use interactive code "@", replacing all uses of
`so-long-menu-click-window'.  This approach leaves the window selected
afterwards, whereas the old code did not; but that is not a problem.
(so-long-menu-click-window, so-long-menu-item-revert): Remove the
deprecated functions.

* test/lisp/so-long-tests/so-long-tests.el
(so-long-tests-so-long-menu-item-replace-action): Update the test.

Co-authored-by: Phil Sainty <psainty@orcon.net.nz>