ext argument of fs::path is not vectorized

[DarwinAwardWinner]

I was surprised to find that the ext argument of fs::path is not vectorized, as demonstrated in the below example:

library(fs)
library(assertthat)

bad_paths <- path("foo", letters[1:3], ext = c("txt1", "txt2", "txt3"))
correct_paths <- paste0("foo/", letters[1:3], ".txt", 1:3)
assert_that(all(bad_paths == correct_paths))
#> Error: Elements 2, 3 of bad_paths == correct_paths are not true

^{Created on 2025-07-20 with reprex v2.1.1}

The function silently takes the first element of ext and uses it for all elements, which leads to unexpected behavior. Either the argument should be modified to accept a vector rather than a scalar, or if not being vectorized is intentional, then it should at least throw an error when passed a vector with length != 1, and this fact should be documented in the help text.