doc: update configuration

README.md

@@ -22,6 +22,7 @@ lsp-mode client leveraging [pyright](https://github.com/microsoft/pyright) and [
 ```emacs-lisp
 (use-package lsp-pyright
   :ensure t
+  :custom (lsp-pyright-langserver-command "pyright") ;; or basedpyright
   :hook (python-mode . (lambda ()
                           (require 'lsp-pyright)
                           (lsp))))  ; or lsp-deferred