plugins/rust-tools: move source files to languages/rust subfolder

plugins/default.nix

@@ -68,7 +68,7 @@
     ./languages/plantuml-syntax.nix
     ./languages/python/jupytext.nix
     ./languages/qmk.nix
-    ./languages/rust-tools.nix
+    ./languages/rust/rust-tools.nix
     ./languages/rustaceanvim.nix
     ./languages/sniprun.nix
     ./languages/tagbar.nix

plugins/languages/rust/rust-tools.nix

@@ -105,7 +105,7 @@ in
         standalone file support
         setting it to false may improve startup time
       '';
-    } // (import ../lsp/language-servers/rust-analyzer-config.nix lib pkgs);
+    } // (import ../../lsp/language-servers/rust-analyzer-config.nix lib pkgs);
   };
   config = mkIf cfg.enable {
     extraPlugins = with pkgs.vimPlugins; [