constructive 0.2.0

• We don't use {styler} anymore, performance is sensibly enhanced as a consequence.
• The package works without having {prettycode} installed, but uses it if it's installed
• We default to using the magrittr pipe %>% for R versions that don't support |>
• NA levels are supported for the classes "factor" and "ordered"
• Environment construction includes variables prefixed with a dot
• When we don't attach the package, we don't need to use constructive:: in the ... before opts_* functions, for instance we can call constructive::construct(cars, opts_data.frame("read.table")).
• quote({}) is now constructed as "{ }" rather than "`{`()"