Make STRING the latest kill in the kill ring.
Set `kill-ring-yank-pointer' to point to it.
If `interprogram-cut-function' is non-nil, apply it to STRING.
Optional second argument REPLACE non-nil means that STRING will replace
the front of the kill ring, rather than being added to the list.
When `save-interprogram-paste-before-kill' and `interprogram-paste-function'
are non-nil, saves the interprogram paste string(s) into `kill-ring' before
When the yank handler has a non-nil PARAM element, the original STRING
argument is not used by `insert-for-yank'. However, since Lisp code
may access and use elements from the kill ring directly, the STRING
argument should still be a "useful" string for such uses.