Fix child layout documentation (#6110)

website/api/layout-BottomTabs.mdx

         name: 'HomeScreen'
       }
     },
-    stack: {
-      id: 'PROFILE_TAB',
-      children: [
-        {
-          component: {
-            id: 'PROFILE_SCREEN',
-            name: 'ProfileScreen'
+    {
+      stack: {
+        id: 'PROFILE_TAB',
+        children: [
+          {
+            component: {
+              id: 'PROFILE_SCREEN',
+              name: 'ProfileScreen'
+            }
           }
-        }
-      ]
+        ]
+      }
     }
   ]
 }

website/docs/docs-bottomTabs.mdx

         }
       }
     },
-    stack: {
-      id: 'PROFILE_TAB',
-      children: [
-        {
-          component: {
-            id: 'PROFILE_SCREEN',
-            name: 'ProfileScreen'
+    {
+      stack: {
+        id: 'PROFILE_TAB',
+        children: [
+          {
+            component: {
+              id: 'PROFILE_SCREEN',
+              name: 'ProfileScreen'
+            }
+          }
+        ],
+        options: {
+          bottomTab: {
+            icon: require('./profile.png')
           }
-        }
-      ],
-      options: {
-        bottomTab: {
-          icon: require('./profile.png')
         }
       }
     }

website/docs/docs-root.mdx

   root: {
     bottomTabs: {
       children: [
-        stack: {
-          children: [
-            {
-              component: {
-                name: 'FEED_SCREEN'
+        {
+          stack: {
+            children: [
+              {
+                component: {
+                  name: 'FEED_SCREEN'
+                }
               }
-            }
-          ]
+            ]
+          }
         },
-        stack: {
-          children: [
-            {
-              component: {
-                name: 'CHAT_LIST'
+        {
+          stack: {
+            children: [
+              {
+                component: {
+                  name: 'CHAT_LIST'
+                }
               }
-            }
-          ]
+            ]
+          }
         },
-        stack: {
-          children: [
-            {
-              component: {
-                name: 'PROFILE_SCREEN'
+        {
+          stack: {
+            children: [
+              {
+                component: {
+                  name: 'PROFILE_SCREEN'
+                }
               }
-            }
-          ]
+            ]
+          }
         }
       ]
     }
       center: {
         stack: {
           children: [
-            name: 'HOME_SCREEN'
+            {
+              component: {
+                name: 'HOME_SCREEN'
+              }
+            }
           ]
         }
       },

website/docs/style-theme.mdx

 // That stack's topBar background color will be red, as is set in default options
 Navigation.setRoot({
   root: {
-    stack :{
+    stack: {
       children: [
         ...
       ]