[Feature Request] el-input: password box should have a closed-eye when password is not revealed

### Existing Component
yes

### Component Name
el-input

### Description
when password is revealed in password box, el-input should have open-eye icon, and when password is hidden, icon should be closed
right now el-input where always show a open-eye icon, which is a little strange compare to other ui library such as antdv.
[element](https://element.eleme.io/#/en-US/component/input#password-box):
and i also notice that Element doesn't have a closed-eye icon, really hope this feature can be added.

[antdv](https://www.antdv.com/components/input/#API):