Doc: fix on-demand examples to support babel 7 (#9504)

* Update quickstart.md

* Update quickstart.md

* Update quickstart.md

* Update quickstart.md

* Adjust on demand import in es docs

examples/docs/en-US/quickstart.md

@@ -57,12 +57,11 @@ Then edit .babelrc:
   "presets": [
     ["es2015", { "modules": false }]
   ],
-  "plugins": [["component", [
-    {
+  "plugins": [["component", {
       "libraryName": "element-ui",
       "styleLibraryName": "theme-chalk"
     }
-  ]]]
+  ]]
 }
 ```
 

examples/docs/es/quickstart.md

@@ -57,12 +57,11 @@ Luego edite .babelrc:
   "presets": [
     ["es2015", { "modules": false }]
   ],
-  "plugins": [["component", [
-    {
+  "plugins": [["component", {
       "libraryName": "element-ui",
       "styleLibraryName": "theme-chalk"
     }
-  ]]]
+  ]]
 }
 ```
 

examples/docs/zh-CN/quickstart.md

@@ -57,12 +57,11 @@ npm install babel-plugin-component -D
   "presets": [
     ["es2015", { "modules": false }]
   ],
-  "plugins": [["component", [
-    {
+  "plugins": [["component", {
       "libraryName": "element-ui",
       "styleLibraryName": "theme-chalk"
     }
-  ]]]
+  ]]
 }
 ```