* ivy.el (ivy--format-function-generic): Third arg is no longer a list
of cons cells, but a list of strings instead.
(ivy-format-function-default):
(ivy-format-function-arrow):
(ivy-format-function-line): Take a string instead of a cons cell.
(ivy--format): Feed strings instead of cons cells to
`ivy-format-function'.
* ivy-test.el (ivy--format): Update test.
* counsel.el (counsel--yank-pop-format-function): Take a string instead
of a cons cell.