[Docs] device mode in devtools docs topnav

BUG=

Review URL: https://codereview.chromium.org/458643002

Cr-Commit-Position: refs/heads/master@{#290737}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@290737 0039d316-1c4b-4281-b951-d872f2087c98

chrome/common/extensions/docs/templates/json/chrome_sidenav.json

@@ -71,8 +71,8 @@
             "href": "/devtools/docs/javascript-debugging"
           },
           {
-            "title": "Mobile Emulation",
-            "href": "/devtools/docs/mobile-emulation"
+            "title": "Device Mode & Mobile Emulation",
+            "href": "/devtools/docs/device-mode"
           },
           {
             "title": "Remote Debugging on Android",