Don't use obsoleted function

[syohex]

nrepl-current-tooling-session is no longer available and cider-current-tooling-session should be used.

See also

• https://github.com/clojure-emacs/cider/commit/705133f2bdca33cb5bc6e0a5b4861965e0883ee4

[phillord]

Ta! I think I have migrated all of the others.

Last I heard, they were thinking of moving cider away from nrepl, then everything will break again!