Previously, this could 'nonc' to a list that shouldn't be modified.
* lisp/eshell/esh-cmd.el (eshell-rewrite-named-command): Use 'append'
instead of 'nconc'.
* test/lisp/eshell/esh-var-tests.el (esh-var-test/interp-var-splice):
(esh-var-test/quoted-interp-var-splice): New tests.