Add innerRef prop to <Link> component

An `innerRef` prop was added to <Link> in `react-router-dom@4.2`

The node will be an anchor tag, which is why I made the callback accept
an `HTMLAnchorElement` rather than an `HTMLElement`, however this isn't
explicitly documented.

types/react-router-dom/index.d.ts

@@ -2,6 +2,7 @@
 // Project: https://github.com/ReactTraining/react-router
 // Definitions by: Tanguy Krotoff <https://github.com/tkrotoff>
 //                 Huy Nguyen <https://github.com/huy-nguyen>
+//                 Philip Jackson <https://github.com/p-jackson>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.6
 
@@ -44,6 +45,7 @@ export class HashRouter extends React.Component<HashRouterProps, any> {}
 export interface LinkProps extends React.AnchorHTMLAttributes<HTMLAnchorElement> {
     to: H.LocationDescriptor;
     replace?: boolean;
+    innerRef?: (node: HTMLAnchorElement | null) => void;
 }
 export class Link extends React.Component<LinkProps, any> {}
 

types/react-router-dom/react-router-dom-tests.tsx

@@ -2,7 +2,8 @@ import * as React from 'react';
 import {
   NavLink,
   NavLinkProps,
-  match
+  match,
+  Link
 } from 'react-router-dom';
 import * as H from 'history';
 
@@ -19,3 +20,8 @@ export default function(props: Props) {
     <NavLink {...rest} isActive={isActive}/>
   );
 }
+
+<Link to="/url" />;
+
+const acceptRef = (node: HTMLAnchorElement | null) => {};
+<Link to="/url" replace={true} innerRef={acceptRef} />;