`replace_na()` will replace any empty input

[DavisVaughan]

tidyr::replace_na(list(character()), replace = "foo")
#> [[1]]
#> [1] "foo"

^{Created on 2021-10-18 by the reprex package (v2.0.1)}

Due to is_complete()'s implementation. It should just replace NULLs

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Not sure why replace_na() is using is_complete()? Should not be using "incompleteness" as a replacement condition, should probably just be using "missingness" (i.e. through vec_equal_na())