Deprecated completions: Show strikethrough across icons or don't show at all

[octref]

Testing #79814:

These strikethroughs are too thing and don't go all the way through. If we do add a strikethrough I hope it can be more clear.

Alternatively we can also remove it for now, so they stay consistent with deprecated symbols where the icons are not affected by deprecated.

[jrieken]

Yeah, that half strikeout shouldn't happen. Today it should only be the word, that's because the icons comes as background images of a ::before-elements which text content isn't wide enough. For now, I will make sure that suggest looks like the others, later, once we have an icon font, we can revisit this.