Move the getAuthToken scopes documentation

The disclaimer for the getAuthToken scopes parameter is currently
directly under getAuthToken general documentation. This change moves it
to a more relevant location (directly under the callback documentation)
so it is closer to what it refers to.

Bug: None
Change-Id: Id13ecb8adbe038dd69b92b3ead2939d19b7a4c73
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2335638
Commit-Queue: William Lin <williamlin@google.com>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794291}

chrome/common/extensions/api/identity.idl

@@ -114,12 +114,11 @@ namespace identity {
     // context. In particular, do not use <code>getAuthToken</code>
     // interactively when your app is first launched.
     //
-    // The <code>scopes</code> parameter in the callback function is not yet
-    // available. It will be populated in future versions of Chrome.
-    //
     // |details| : Token options.
     // |callback| : Called with an OAuth2 access token as specified by the
-    // manifest, or undefined if there was an error.
+    // manifest, or undefined if there was an error. The <code>scopes</code>
+    // parameter is not yet available. It will be populated in future versions
+    // of Chrome.
     static void getAuthToken(optional TokenDetails details,
                              optional GetAuthTokenCallback callback);