Add ruby-lsp extensions to Useful Tools in README.md (#1735)

Author: johansenja

README.md

@@ -62,6 +62,7 @@ Useful Tools
 ------------
 
 * [FactoryTrace](https://github.com/djezzzl/factory_trace) - helps to find unused factories and traits.
+* [ruby-lsp-factory_bot](https://github.com/donny741/ruby-lsp-factory_bot) / [ruby-lsp-rails-factory-bot](https://github.com/johansenja/ruby-lsp-rails-factory-bot) - integration with [ruby-lsp](https://github.com/Shopify/ruby-lsp) to provide intellisense
 
 Contributing
 ------------