Improve documentation of recent changes in Comint

Improve documentation of recent changes in Comint

* lisp/comint.el (comint-insert-previous-argument)
(comint-arguments, comint-insert-previous-argument-from-end):
Doc fixes.
(comint-insert-previous-argument-from-end): Add :version.

* doc/emacs/misc.texi (Shell Ring): Fix a typo in the name of
'comint-insert-previous-argument'.  Document
'comint-insert-previous-argument-from-end'.  (Bug#25271)

* etc/NEWS: Reformat and rephrase the entry for recent Comint
changes.