vimPlugins.markview-nvim: remove nvim-web-devicons dependency

Doesn't seem to be a hard dependency and is causing issues downstream.
nix-community/nixvim#2339

Author: khaneliman

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

@@ -1131,10 +1131,6 @@ in
       '';
     };
 
-  markview-nvim = super.markview-nvim.overrideAttrs {
-    dependencies = with self; [ nvim-web-devicons ];
-  };
-
   mason-lspconfig-nvim = super.mason-lspconfig-nvim.overrideAttrs {
     dependencies = with self; [ mason-nvim nvim-lspconfig ];
   };