When using kitty or terminal that supports emoji, `Void` should not jump but print spacers

[nazmulidris]

Currently, when using terminals that do no support emoji (jumbo ones especially), the behavior is consistently "broken". However, on terminal emulators like kitty that do support jumbo emoji, the behavior is ironically broken 😄 . The reason is that PixelChar::Void is rendered to OffscreenBuffer it simply skips, and does not paint Spacers. It should do that to fix the issues w/ kitty.