Add useDeferredValue hook snippet and update README

Author: alDuncanson

README.md

@@ -13,6 +13,7 @@ React Hooks Snippets is a [Visual Studio Code](https://code.visualstudio.com/) e
 | ------------- | ------------- |
 | `ush` | `useState` |
 | `uth` | `useTransitionHook` |
+| `udvh` | `useDeferredValue` |
 | `ueh` | `useEffect` |
 | `uleh` | `useLayoutEffect` |
 | `uieh` | `useInsertionEffect` |

snippets/snippets.json

@@ -13,6 +13,13 @@
 		],
 		"description": "React useTransition() hook"
 	},
+	"useDeferredValue": {
+		"prefix": "udvh",
+		"body": [
+			"const ${1:deferredValue} = useDeferredValue(${2:value});$0"
+		],
+		"description": "React useDeferredValue() hook"
+	},
 	"useEffect": {
 		"prefix": "ueh",
 		"body": [