str_ascii_ascii Function

   pure function str_ascii_ascii(input) result(output)
   !< Convert string of ASCII kind to ASCII string, just for convenience in sanitize strings.
   !<
   !<```fortran
   !< use penf
   !< character(len=:, kind=ASCII), allocatable :: string
   !< string = str_ascii('I was ASCII kind and I am still ASCII')
   !< print "(A)", string
   !<```
   !=> I was ASCII kind and I am still ASCII <<<
   character(len=*, kind=ASCII), intent(in)  :: input  !< Input string of ASCII kind.
   character(len=:, kind=ASCII), allocatable :: output !< Output string of ASCII kind.

   output = input
   endfunction str_ascii_ascii