fix(rust): incorporate latest changes from rustaceanvim (#3655)

## What is this PR for?

After recent changes in `rustaceanvim` in
https://github.com/mrcjkb/rustaceanvim/pull/403, `checkOnSave` is
supposed to be boolean and the table that we were passing to
`checkOnSave` previously should be passed to `check` instead. I left the
`check` table undefined, because the options that we were passing to
`checkOnSave` before are the default ones being passed to `check`. So,
only if the user wants to change something should he change the values
of the `check` table according to what he wants.

## Does this PR fix an existing issue?

No
## Checklist

- [x] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

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

@@ -65,11 +65,7 @@ return {
               },
             },
             -- Add clippy lints for Rust.
-            checkOnSave = {
+            checkOnSave = true,
-              allFeatures = true,
-              command = "clippy",
-              extraArgs = { "--no-deps" },
-            },
             procMacro = {
               enable = true,
               ignored = {