Fix documents for `mrb_ary_splice()` [ci skip]
@@ -249,10 +249,10 @@ MRB_API mrb_value mrb_ary_entry(mrb_value ary, mrb_int offset);
*
* Equivalent to:
*
- * ary.shift
+ * ary[head, len] = rpl
*
* @param mrb The mruby state reference.
- * @param self The array from which the value will be shifted.
+ * @param self The array from which the value will be partiality replaced.
* @param head Beginning position of a replacement subsequence.
* @param len Length of a replacement subsequence.
* @param rpl The array of replacement elements.
