docs(vue): remove extra callbackFunction parameter (#1234)

Author: rydash

docs/vue-testing-library/api.mdx

@@ -35,7 +35,7 @@ Library.
 It takes up to 2 parameters and returns an object with some helper methods.
 
 ```js
-function render(Component, options, callbackFunction) {
+function render(Component, options) {
   return {
     ...DOMTestingLibraryQueries,
     container,