Support import package

[toscm]

Hi everyone, thanks for your amazing work!

Is it possible to somehow get code completion for packages imported through the import package?

In particular I'm interested in packages and/or scripts imported into new environments. Example:

gg <- import::from("ggplot2", .all=T, .into={new.env()}, .character_only=T)
gg$ggplot(data.frame(x=1:10, y=1:10), gg$aes(x, y)) + gg$geom_point()

# Lines below assume there is a file `xyz.R` in your working dir defining `func`
xyz <- import::from("xyz.R", .all=T, .into={new.env()}, .character_only=T)
xyz$func(1:10)

[eitsupi]

Maybe duplicate of #257