nix: rename custom -> packages

nix/custom/mkNerdFont.nix

@@ -1,63 +0,0 @@
-{
-  nerd-font-patcher,
-  parallel,
-  stdenvNoCC,
-}:
-{
-  font,
-  extraArgs ? [ ],
-  useDefaultsArgs ? true,
-}:
-stdenvNoCC.mkDerivation {
-  /*
-    Credits:
-    https://github.com/NixOS/nixpkgs/issues/44329#issuecomment-1231189572
-    https://github.com/NixOS/nixpkgs/issues/44329#issuecomment-1544597422
-
-    long font names is not problematic:
-    https://github.com/ryanoasis/nerd-fonts/issues/1018#issuecomment-1953555781
-  */
-  name = "${font.name}-NerdFont";
-  src = font;
-  nativeBuildInputs = [
-    nerd-font-patcher
-    parallel
-  ];
-
-  buildPhase =
-    let
-      args = builtins.concatStringsSep " " extraArgs;
-      defArgs =
-        if useDefaultsArgs then
-          builtins.concatStringsSep " " [
-            "--careful"
-            "--complete"
-            "--quiet"
-            "--no-progressbars"
-          ]
-        else
-          "";
-    in
-    ''
-      mkdir -p nerd-font
-      find \( -name \*.ttf -o -name \*.otf \) | parallel nerd-font-patcher {} \
-          --outputdir nerd-font ${defArgs} ${args}
-    '';
-
-  installPhase = ''
-    exists() { [ -e "$1" ]; }
-
-    truetype="$out/share/fonts/truetype"
-    opentype="$out/share/fonts/opentype"
-
-    if exists nerd-font/*.ttf ; then
-      mkdir -p "$truetype"
-      cp nerd-font/*.ttf "$truetype"
-    fi
-
-    if exists nerd-font/*.otf ; then
-      mkdir -p "$opentype"
-      cp nerd-font/*.otf "$opentype"
-    fi
-  '';
-}