neovim: fixed luasnip test + simplify code

let's not use vimrcContent that is effectively the identity in our context.

pkgs/applications/editors/neovim/tests/default.nix

@@ -364,7 +364,6 @@ in
   # for instance luasnip has a dependency on jsregexp
   can_require_transitive_deps =
     runTest nvim-with-luasnip ''
-    cat ${nvim-with-luasnip}/nvim
     ${nvim-with-luasnip}/bin/nvim -i NONE --cmd "lua require'jsregexp'" -e +quitall!
   '';
 

pkgs/applications/editors/neovim/wrapper.nix

@@ -84,13 +84,9 @@ let
     pluginRC = lib.foldl (acc: p: if p.config != null then acc ++ [p.config] else acc) []  pluginsNormalized;
 
     # a limited RC script used only to generate the manifest for remote plugins
-    manifestRc = vimUtils.vimrcContent { customRC = ""; };
+    manifestRc = "";
     # we call vimrcContent without 'packages' to avoid the init.vim generation
-    neovimRcContent' = vimUtils.vimrcContent {
-      beforePlugins = "";
-      customRC = lib.concatStringsSep "\n" (pluginRC ++ lib.optional (neovimRcContent != null) neovimRcContent);
-      packages = null;
-    };
+    neovimRcContent' = lib.concatStringsSep "\n" (pluginRC ++ lib.optional (neovimRcContent != null) neovimRcContent);
 
     packpathDirs.myNeovimPackages = myVimPackage;
     finalPackdir = neovimUtils.packDir packpathDirs;