fix flycheck for rust, add lsp and cargo support

lib/extensions/rust.el

@@ -7,7 +7,8 @@
 
 ;; dependencies
 (depends-on 'rust-mode)
-
+(depends-on 'cargo)
+(depends-on 'flycheck-rust)
 (extension rust
            :version 0.0.1
            :on-initialize extensions/rust-initialize

lib/extensions/rust/init.el

@@ -3,7 +3,9 @@
 ;;; Code:
 
 (defun extensions/rust-initialize ()
-  "Initialize Rust extension.")
-
+  "Initialize Rust extension."
+  (add-hook 'rust-mode-hook #'lsp)
+  (add-hook 'rust-mode-hook #'cargo-minor-mode)
+  (add-hook 'flycheck-mode-hook #'flycheck-rust-setup))
 (provide 'extensions/rust/init)
 ;;; init ends here.