Standardize arguments in `...` of mapping functions

[rossellhayes]

library(gradethis)
library(purrr)

gradethis:::call_standardise_formals(quote(
  map(list(1:10, 1:20), mean, 0.1, TRUE)
))
#> map(.x = list(1:10, 1:20), .f = mean, trim = 0.1, na.rm = TRUE, 
#>     .progress = FALSE)

code_feedback(
  user_code     = "map(list(1:10, 1:20), mean, 0.1, TRUE)",
  solution_code = "map(list(1:10, 1:20), mean, trim = 0.1, na.rm = TRUE)"
)
#> NULL

^{Created on 2023-05-01 with reprex v2.0.2}

Closes #343.