[Bug Report] Date Range (With quick options) issue in Documentation

### Element UI version
2.15.7

### OS/Browsers version
Google Chrome Version 96.0.4664.55 (Official Build) (x86_64)

### Vue version
2.6.14

### Reproduction Link
https://jsfiddle.net/h4p2kaeq/1/

### Steps to reproduce
1. component -> Date Range
2. use Date Range with Quick Options
3. click on last week option in the left panel

### What is Expected?
The selected last week's dates should be highlighted in the calendar.

### What is actually happening?
It is showing the right dates when the date range input box but when we click to open the calendar view the wrong week dates are highlighted with incorrect months.