Fix a docstring and a compilation warning

Author: bbatsov

clojure-mode.el

@@ -2619,10 +2619,11 @@ lists up."
 ;;;###autoload
 (defun clojure-let-backward-slurp-sexp (&optional n)
   "Slurp the s-expression before the let form into the let form.
-With a numberic prefix argument slurp the previous N s-expression into the let form."
+With a numberic prefix argument slurp the previous N s-expression
+into the let form."
   (interactive "p")
   (unless n (setq n 1))
-  (dotimes (k n)
+  (dotimes (_ n)
     (save-excursion (clojure--let-backward-slurp-sexp-internal))))
 
 (defun clojure--let-forward-slurp-sexp-internal ()