xsane: move to by-name

pkgs/top-level/all-packages.nix

···
     openssl = openssl_1_1;
   };
 
-  xsane = callPackage ../applications/graphics/sane/xsane.nix { };
-
   xsw = callPackage ../applications/misc/xsw {
     # Enable the next line to use this in terminal.
     # Note that it requires sixel capable terminals such as mlterm