Add plugin "Ui Suggest Classes" in the readme (#4746)

README.md

@@ -174,6 +174,7 @@ $ yarn test
 * [grapesjs-firestore](https://github.com/artf/grapesjs-firestore) - Storage wrapper for [Cloud Firestore](https://firebase.google.com/docs/firestore)
 * [grapesjs-parser-postcss](https://github.com/artf/grapesjs-parser-postcss) - Custom CSS parser for GrapesJS by using [PostCSS](https://github.com/postcss/postcss)
 * [grapesjs-typed](https://github.com/artf/grapesjs-typed) - Typed component made by wrapping Typed.js library
+* [grapesjs-ui-suggest-classes](https://github.com/lexoyo/grapesjs-ui-suggest-classes) - Enable auto-complete of classes in the SelectorManager UI 
 
 ### Presets
 * [grapesjs-preset-webpage](https://github.com/artf/grapesjs-preset-webpage) - Webpage Builder