exported var/const XYZ should have its own declaration

``` go
package demo

const Hello1, hello2 = 1, 2 // This is valid

const Hello3, Hello4 = 3, 4 // exported const Hello4 should have its own declaration

var Hello5, hello6 int // This is valid

var Hello7, Hello8 int // exported var Hello8 should have its own declaration
```
