Further Tramp code cleanup

Further Tramp code cleanup

* doc/misc/tramp.texi (Predefined connection information):
Mention "about-args".

* lisp/net/tramp-cmds.el (tramp-version): Adapt docstring.

* lisp/net/tramp.el (tramp-handle-expand-file-name):
* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-expand-file-name):
* lisp/net/tramp-sh.el (tramp-sh-handle-expand-file-name)
* lisp/net/tramp-smb.el (tramp-smb-handle-expand-file-name):
* lisp/net/tramp-sudoedit.el (tramp-sudoedit-handle-expand-file-name):
Handle local "/..".

* lisp/net/tramp-rclone.el (tramp-methods) <rclone>:
Adapt `tramp-mount-args'.
(tramp-rclone-flush-directory-cache): Remove.
(tramp-rclone-do-copy-or-rename-file)
(tramp-rclone-handle-delete-directory)
(tramp-rclone-handle-delete-file)
(tramp-rclone-handle-make-directory): Don't use that function.
(tramp-rclone-maybe-open-connection): Fix use of `tramp-mount-args'.

* lisp/net/trampver.el (tramp-inside-emacs): New defun.
* lisp/net/tramp.el (tramp-handle-make-process):
* lisp/net/tramp-sh.el (tramp-sh-handle-make-process)
(tramp-sh-handle-process-file, tramp-open-shell): Use it.
(tramp-get-env-with-u-option): Remove.

* test/lisp/net/tramp-tests.el (tramp-test05-expand-file-name-top):
New test.