[new feature] add sticky component (#3888)

docs/markdown/intro.en-US.md

@@ -8,7 +8,7 @@
 
 ### Features
 
-* 60 Reusable components
+* 60+ Reusable components
 * 90% Unit test coverage
 * Extensive documentation and demos
 * Support [babel-plugin-import](https://github.com/ant-design/babel-plugin-import)

docs/markdown/intro.zh-CN.md

@@ -8,7 +8,7 @@
 
 ### 特性
 
-* 60 个组件
+* 60+ 个组件
 * 90% 单元测试覆盖率
 * 完善的中英文文档和示例
 * 支持按需引入

docs/site/doc.config.js

@@ -267,6 +267,10 @@ export default {
                 path: '/steps',
                 title: 'Steps 步骤条'
               },
+              {
+                path: '/sticky',
+                title: 'Sticky 粘性布局'
+              },
               {
                 path: '/swipe',
                 title: 'Swipe 轮播'
@@ -605,6 +609,10 @@ export default {
                 path: '/steps',
                 title: 'Steps'
               },
+              {
+                path: '/sticky',
+                title: 'Sticky'
+              },
               {
                 path: '/swipe',
                 title: 'Swipe'