use across with scoped variants with replace_with_na (e.g., _if _at _all)

[njtierney]

Following on for #262 I would like to have replace_with_na work with across and co, or to document a way to use across with na_if or other solutions.

Related issues:

• allowing the use of vars() and select helpers in replace_with_na_at #125
• Using across() and co instead of scoped variants (_if, _at, _all) #262
• replace_with_na_all seems to be very slow compared to the base R solution #143