Request: Create proper size window according to current window layout

## Issue template

#### Issue description

The core command to open CtrlSF window is:
```
'botright vertical'. winsize .'split'
```
Vim will create a window which width = `winsize`

If remove the `winsize`:
```
'botright vertical split'
```
Vim will create a window with a proper window size according to current window layout.

Could you add a flag to support this behavior?