github-electron: add missing remote.getCurrentWebContents()

API document is here:

https://github.com/atom/electron/blob/master/docs/api/remote.md#remotegetcurrentwebcontents

github-electron/github-electron-renderer-tests.ts

@@ -38,6 +38,8 @@ remote.getCurrentWindow().capturePage(buf => {
 	});
 });
 
+remote.getCurrentWebContents().print();
+
 remote.getCurrentWindow().capturePage(buf => {
 	remote.require('fs').writeFile('/tmp/screenshot.png', buf, (err: Error) => {
 		console.log(err);

github-electron/github-electron.d.ts

@@ -1541,6 +1541,10 @@ declare module Electron {
 		 * @returns The BrowserWindow object which this web page belongs to.
 		 */
 		getCurrentWindow(): BrowserWindow;
+		/**
+		 * @returns The WebContents object of this web page.
+		 */
+		getCurrentWebContents(): WebContents;
 		/**
 		 * @returns The global variable of name (e.g. global[name]) in the main process.
 		 */