vimPlugins.nvim-treesitter: allow overlay changes to affect queries packages

The upstream nvim-treesitter defines tree-sitter queries for many
languages. Those are made available as separate packages in nixpkgs via
derivations that symlink to subdirectories in
vimPlugins.nvim-treesitter's src input. But derivations for those
queries packages are defined in an overlay where nvim-treesitter is
referenced via `super` instead of `self`. That means that if end users
patch nvim-treesitter's src input, changes do not propagate to the
queries packages.

This change switches nvim-treesitter references from attributes on
`super` to use `self` instead.

pkgs/applications/editors/vim/plugins/nvim-treesitter/overrides.nix

@@ -37,8 +37,8 @@ let
         }
         ''
           mkdir -p "$out/queries"
-          if [ -d "${super.nvim-treesitter.src}/runtime/queries/${language}" ]; then
-            ln -s "${super.nvim-treesitter.src}/runtime/queries/${language}" "$out/queries/${language}"
+          if [ -d "${self.nvim-treesitter}/runtime/queries/${language}" ]; then
+            ln -s "${self.nvim-treesitter}/runtime/queries/${language}" "$out/queries/${language}"
           else
             echo "Error: there are no queries for ${language}."
             exit 1