* lisp/thingatpt.el (thing-at-point-bounds-of-list-at-point): Revert
to pre 26.1 behavior. Return whole sexp at point if no enclosing
list.
(list-at-point): New optional arg to ignore comments and strings.
* test/lisp/thingatpt-tests.el
(thing-at-point-bounds-of-list-at-point): Fix and augment tests.