extensions docs: fix typo

Fixed: 1059652
Change-Id: Ifef9249335ce99da2adb5453b2a831755392bbc9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2115752Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#752813}

chrome/common/extensions/docs/templates/articles/tut_debugging.html

@@ -99,7 +99,7 @@
   Now that the extension initializes correctly,
   other components can be tested.
   Refresh this page,
-  or open a new tab and naigate to any page on developer.chrome.com,
+  or open a new tab and navigate to any page on developer.chrome.com,
   open the popup and click the green square.
   And... nothing happens.
 </p>