Add installation instructions for suggested packages

[pkq]

I thought these might be useful, given how little slidex can do without them. 😉

[datalorax]

Beautiful! Before I merge this, would you mind also adding in {tibble} as a suggests? I keep meaning to add that but forgetting. tibble::tribble is used when reproducing tables.

[pkq]

Will do! Hold on a sec.

[pkq]

Actually, I think that'd fit better with #12. I'll do that there?

[pkq]

Wait, I see what you mean. Yeah, here makes sense.

[datalorax]

Thanks so much!