fix a help page CSS transition

It now matches the timing and timing function of the advanced options section in settings.

BUG=none

Review URL: https://codereview.chromium.org/99873002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238356 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/help/help.css

@@ -101,7 +101,7 @@ body {
 }
 
 #more-info-container {
-  -webkit-transition: all 500ms linear;
+  -webkit-transition: all 200ms;
   height: 0;
   margin-bottom: 0;
   overflow: hidden;