vimPlugins.perfanno-nvim: remove gperf dependency

gperf is not a hard dependency, and it would be incorrect to require
gperf be installed via nix on a non nixos system.

pkgs/applications/editors/vim/plugins/overrides.nix

@@ -2910,8 +2910,6 @@ assertNoAdditions {
   });
 
   perfanno-nvim = super.perfanno-nvim.overrideAttrs (old: {
-    dependencies = [ gperf ];
-
     meta = old.meta // {
       maintainers = with lib.maintainers; [ fredeb ];
     };