New review comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/27014#discussion_r539610401

Comment:
```suggestion
depends="$(vopt_if systemqt 'qt5 qt5-graphicaleffects qt5-imageformats qt5-quickcontrols qt5-quickcontrols2 qt5-svg qt5-script qt5-declarative')
 xcb-util-image xcb-util-keysyms"
```

We indent multi-line variables with spaces