feat: add formatter for rust

lua/lazyvim/plugins/extras/lang/rust.lua

@@ -113,6 +113,21 @@ return {
     },
   },
 
+  {
+    "stevearc/conform.nvim",
+    optional = true,
+    opts = {
+      formatters = {
+        rustfmt = {
+          command = "rustfmt",
+        },
+      },
+      formatters_by_ft = {
+        ["rust"] = { "rustfmt" },
+      },
+    },
+  },
+
   {
     "nvim-neotest/neotest",
     optional = true,