fix(modal): when title large hidden close icon (#535)

components/modal/demo/largeTitle.md

@@ -0,0 +1,58 @@
+---
+order: 6
+title:
+  zh-CN: 超长 Title
+---
+
+## zh-CN
+
+弹框中包含表格
+
+```jsx
+import { Modal, Button, Table } from 'antd';
+
+class App extends React.Component {
+  state = { visible: false };
+
+  showModal = () => {
+    this.setState({
+      visible: true,
+    });
+  };
+
+  handleOk = e => {
+    console.log(e);
+    this.setState({
+      visible: false,
+    });
+  };
+
+  handleCancel = e => {
+    console.log(e);
+    this.setState({
+      visible: false,
+    });
+  };
+
+  render() {
+    return (
+      <div>
+        <Button type="primary" onClick={this.showModal}>
+          Open Modal
+        </Button>
+        <Modal
+          title="xixiixixixixiixxixiix超长名字嘻嘻超长名字嘻嘻超长名字嘻嘻超长名字嘻嘻超长名字嘻嘻"
+          width={520}
+          visible={this.state.visible}
+          onOk={this.handleOk}
+          onCancel={this.handleCancel}
+        >
+          内容
+        </Modal>
+      </div>
+    );
+  }
+}
+
+ReactDOM.render(<App />, mountNode);
+```

theme/dt-theme/default/modal.less

@@ -1,6 +1,7 @@
 @import "../const.less";
 
 .ant-modal-title {
+    padding-right: 10px;
     font-weight: 600;
 }