transform-(with-)nth: use whole output, no cycling

- Rotation of '|'-separated values applied to transform and
  bg-transform variants, where a.a is the command template
- Output '1|2' turned the binding into '2|1', run as a shell
  command on the next key press
- Output was also cut at '|', breaking --with-nth templates
  like '{2}|{1}'
- Split and rotate only for change-nth and change-with-nth

man/man1/fzf.1

@@ -2166,8 +2166,8 @@ A key or an event can be bound to one or more of the following actions.
     \fBtransform\-header\-label(...)\fR  (transform header label using an external command)
     \fBtransform\-input\-label(...)\fR   (transform input label using an external command)
     \fBtransform\-list\-label(...)\fR    (transform list label using an external command)
-    \fBtransform\-nth(...)\fR           (transform nth using an external command)
-    \fBtransform\-with\-nth(...)\fR      (transform with-nth using an external command)
+    \fBtransform\-nth(...)\fR           (transform nth using an external command; no rotation, output is used as a whole)
+    \fBtransform\-with\-nth(...)\fR      (transform with-nth using an external command; no rotation, output is used as a whole)
     \fBtransform\-pointer(...)\fR       (transform pointer using an external command)
     \fBtransform\-preview\-label(...)\fR (transform preview label using an external command)
     \fBtransform\-prompt(...)\fR        (transform prompt string using an external command)