feat: export more ts definition (#13)

Author: vagusX

docs/examples/controlled.tsx

@@ -1,9 +1,10 @@
 import '../../assets/style.less';
 import React from 'react';
-import Segmented, { SegmentedValue } from 'rc-segmented';
+import Segmented from 'rc-segmented';
+import type { SegmentedValue } from 'rc-segmented';
 
 export default class Demo extends React.Component<
-  {},
+  unknown,
   { value: SegmentedValue }
 > {
   state = {

src/index.tsx

@@ -7,9 +7,9 @@ import omit from 'rc-util/lib/omit';
 
 export type SegmentedValue = string | number;
 
-type SegmentedRawOption = SegmentedValue;
+export type SegmentedRawOption = SegmentedValue;
 
-interface SegmentedLabeledOption {
+export interface SegmentedLabeledOption {
   className?: string;
   disabled?: boolean;
   label: React.ReactNode;