iosevka: Fix build phase not to print progress messages
iosevka: Fix build phase not to print progress messages

My commit below removed a `> /dev/null` from fonts/iosevka/default.nix
by mistake.

  89d24b58b25cc5778eeeccfb82cb024fa08edbac
  Author:      Damien Cassou <damien@cassou.me>
  AuthorDate:  Mon Jun 6 18:26:06 2022 +0200

  iosevka-comfy: init at 0.1.0

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs