fix: code style in reactivity-computed-watchers.md (#1126)

Author: skirtles-code

src/guide/reactivity-computed-watchers.md

@@ -95,8 +95,7 @@ An async function implicitly returns a Promise, but the cleanup function needs t
 
 Vue's reactivity system buffers invalidated effects and flushes them asynchronously to avoid unnecessary duplicate invocation when there are many state mutations happening in the same "tick". Internally, a component's `update` function is also a watched effect. When a user effect is queued, it is by default invoked **before** all component `update` effects:
 
-```html
-
+```vue
 <template>
   <div>{{ count }}</div>
 </template>
@@ -201,15 +200,15 @@ watch(count, (count, prevCount) => {
 A watcher can also watch multiple sources at the same time using an array:
 
 ```js
-const firstName = ref('');
-const lastName = ref('');
+const firstName = ref('')
+const lastName = ref('')
 
 watch([firstName, lastName], (newValues, prevValues) => {
-  console.log(newValues, prevValues);
+  console.log(newValues, prevValues)
 })
 
-firstName.value = "John"; // logs: ["John",""] ["", ""]
-lastName.value = "Smith"; // logs: ["John", "Smith"] ["John", ""]
+firstName.value = 'John' // logs: ["John", ""] ["", ""]
+lastName.value = 'Smith' // logs: ["John", "Smith"] ["John", ""]
 ```
 
 ### Watching Reactive Objects
@@ -222,71 +221,72 @@ const numbers = reactive([1, 2, 3, 4])
 watch(
   () => [...numbers],
   (numbers, prevNumbers) => {
-    console.log(numbers, prevNumbers);
-  })
+    console.log(numbers, prevNumbers)
+  }
+)
 
 numbers.push(5) // logs: [1,2,3,4,5] [1,2,3,4]
 ```
 
 Attempting to check for changes of properties in a deeply nested object or array will still require the `deep` option to be true:
 
 ```js
-const state = reactive({ 
-  id: 1, 
-  attributes: { 
-    name: "",
-  },
-});
+const state = reactive({
+  id: 1,
+  attributes: {
+    name: ''
+  }
+})
 
 watch(
   () => state,
   (state, prevState) => {
     console.log(
-      "not deep ",
+      'not deep',
       state.attributes.name,
       prevState.attributes.name
-    );
+    )
   }
-);
+)
 
 watch(
   () => state,
   (state, prevState) => {
     console.log(
-      "deep ",
+      'deep',
       state.attributes.name,
       prevState.attributes.name
-    );
+    )
   },
   { deep: true }
-);
+)
 
-state.attributes.name = "Alex"; // Logs: "deep " "Alex" "Alex"
+state.attributes.name = 'Alex' // Logs: "deep" "Alex" "Alex"
 ```
 
 However, watching a reactive object or array will always return a reference to the current value of that object for both the current and previous value of the state. To fully watch deeply nested objects and arrays, a deep copy of values may be required. This can be achieved with a utility such as [lodash.cloneDeep](https://lodash.com/docs/4.17.15#cloneDeep)
 
 ```js
-import _ from 'lodash';
+import _ from 'lodash'
 
 const state = reactive({
   id: 1,
   attributes: {
-    name: "",
-  },
-});
+    name: ''
+  }
+})
 
 watch(
   () => _.cloneDeep(state),
   (state, prevState) => {
     console.log(
-      state.attributes.name, 
+      state.attributes.name,
       prevState.attributes.name
-    );
+    )
   }
-);
+)
 
-state.attributes.name = "Alex"; // Logs: "Alex" ""
+state.attributes.name = 'Alex' // Logs: "Alex" ""
 ```
 
 ### Shared Behavior with `watchEffect`