neovim: revert the linker changes that cause issues on nix

some linker flags have been added to support declarative treesitter grammars but the justification is fuzzy and it breaks several stuff on nix see https://github.com/NixOS/nixpkgs/pull/147658

pkgs/applications/editors/neovim/default.nix

@@ -113,12 +113,6 @@ in
       substituteInPlace src/nvim/CMakeLists.txt --replace "    util" ""
     '';
 
-    # For treesitter plugins, libstdc++.so.6, or equivalent will be needed
-    NIX_LDFLAGS =
-      lib.optionals stdenv.cc.isGNU [ "-lstdc++"]
-      ++ lib.optionals stdenv.cc.isClang [ "-lc++" ];
-
-    # export PATH=$PWD/build/bin:${PATH}
     shellHook=''
       export VIMRUNTIME=$PWD/runtime
     '';