Problem: A leading space in the result of a %{} item is sometimes
stripped, and an all-digit result is converted to a number.
Solution: Add %0{} atom which inserts the expression result verbatim
(glepnir)
fixes: vim/vim#3898closes: vim/vim#20315e8d7a40b98
Co-authored-by: glepnir <glephunter@gmail.com>