`geom_cens()` uses aesthetics of `CENS` and `LIMIT` rather than `lower` and `upper`

[billdenney]

This line:

nlmixr2plot/R/plot.nlmixr2.R

Line 284 in 85b40df

geom_cens(ggplot2::aes(lower = .data$lowerLim, upper = .data$upperLim), fill = "purple")

Causes warnings of:

1: In geom_cens(ggplot2::aes(lower = .data$lowerLim, upper = .data$upperLim),  :
  Ignoring unknown aesthetics: lower and upper