feat(file_t): output to file with character name

This commit converts the write_lines name to be a generic binding
on the file_t derived type with two corresponding private specific
type-bound procedures: one with string_t file_name dummy argument
and one with a character(len=*) file_name dummy argument.

src/julienne/julienne_file_m.f90

@@ -1,18 +1,20 @@
 ! Copyright (c) 2024, The Regents of the University of California and Sourcery Institute
 ! Terms of use are as specified in LICENSE.txt
 module julienne_file_m
-  !! A representation of a file as an object
+  !! a representation of a file as an object
   use julienne_string_m, only : string_t
 
   private
   public :: file_t
 
   type file_t
+    !! encapsulate a ragged-edged array of character variables supporting input/output services
     private
     type(string_t), allocatable :: lines_(:)
   contains
     procedure :: lines
-    procedure :: write_lines
+    generic   :: write_lines => to_file_with_string_t_file_name, to_file_with_character_file_name
+    procedure, private       :: to_file_with_string_t_file_name, to_file_with_character_file_name
   end type
 
   interface file_t
@@ -45,12 +47,18 @@ pure module function lines(self)  result(my_lines)
       type(string_t), allocatable :: my_lines(:)
     end function
 
-    impure elemental module subroutine write_lines(self, file_name)
+    impure elemental module subroutine to_file_with_string_t_file_name(self, file_name)
       implicit none
       class(file_t), intent(in) :: self
       type(string_t), intent(in), optional :: file_name
     end subroutine
 
+    impure elemental module subroutine to_file_with_character_file_name(self, file_name)
+      implicit none
+      class(file_t), intent(in) :: self
+      character(len=*), intent(in), optional :: file_name
+    end subroutine
+
   end interface
 
 end module julienne_file_m

src/julienne/julienne_file_s.F90

@@ -18,7 +18,11 @@
     my_lines = self%lines_
   end procedure
 
-  module procedure write_lines
+  module procedure to_file_with_character_file_name
+    call self%write_lines(string_t(file_name))
+  end procedure
+
+  module procedure to_file_with_string_t_file_name
 
     integer file_unit, io_status, l