Hi,
I believe I found a bug in `vi-change-whole-line`.

Minimal zshrc allowing to reproduce the issue:
```
bindkey -v
```

## Steps to reproduce:
1. type 2 words, for example `word1 word2`
2. enter vicmd mode and move cursor to the beginning of first word (`esc`
`0`)
3. use `vi-change` to change word then go back to vicmd (`c` `w` `esc`)
4. use `vi-change-whole-line`

## Expected result:
Kill the current line and enter insert mode.

## Actual result:
The line is killed but the cursor is positioned one place to the right
making the line not empty (line contains single space)

I attach gif recording presenting the issue.
zsh version: 5.6.2 (x86_64-debian-linux-gnu)

All the best,
Kuba