evil visual mode下用cousnel-yank-pop不能自动替换region，而是会直接插入。
解决方法是在visual mode下插入之前删除region
(defun moon-override-yank-pop (&optional arg)
"Delete the region before inserting poped string."
(when (and evil-mode (eq 'visual evil-state))
(kill-region (region-beginning) (region-end))))
(advice-add 'counsel-yank-pop :before #'moon-override-yank-pop)