Parenthesised [] pipelines

Sorry if not relevant, I was not capable of finding my answer in the docs and there's no discussion Q&A section in this repo, so I ask my question here.

I want to have my project to format the code in this way:

library(data.table)
cw <- data.table(ChickWeight)

# fmt: skip
cw21 <- (
  cw[Time %in% c(0, 21)]
  [, Weight := weight] 
  [, Group := factor(paste0("Diet_", Diet))]
  [, .(Chick, Group, Time, Weight)]
  [order(Chick, Time)]
  [1:5]
)

By default, is formatted this way:

# Air formatter by default
cw21 <- (cw[Time %in% c(0, 21)][, Weight := weight][,
  Group := factor(paste0("Diet_", Diet))
][, .(Chick, Group, Time, Weight)][order(Chick, Time)][1:5])

I tried different options in air.toml file skip formatting options, but I'm lost.

# Air formatter with air.toml with [format] skip = ["[", "]", "`[`", "`]`"]
cw21 <- (cw[Time %in% c(0, 21)][, Weight := weight][,
  Group := factor(paste0("Diet_", Diet))
][, .(Chick, Group, Time, Weight)][order(Chick, Time)][1:5])

No files, tests, or entry points are named. Start by locating the formatter logic for parenthesised R expressions and chained [] calls, then compare it with the requested multiline output; done means the example formats as shown without relying on skip settings.