overlays: Drop neovim-unwrapped

Not interested in rebuilding neovim every time just for the desktop icon
to work when I don't use it anyway.

overlays/neovim-unwrapped.nix

@@ -1,13 +0,0 @@
-final: prev: {
-  neovim-unwrapped = prev.neovim-unwrapped.overrideAttrs (oldAttrs: {
-    postInstall =
-      (oldAttrs.postInstall or "")
-      # bash
-      + ''
-        substituteInPlace $out/share/applications/nvim.desktop \
-          --replace "TryExec=nvim" "" \
-          --replace "Terminal=true" "Terminal=false" \
-          --replace "Exec=nvim %F" "Exec=kitty nvim %F"
-      '';
-  });
-}