Respect Toolbar height when jumping to Anchor on Admin page

This emerged as a followup of #598758: Modules page: add link to its settings page for each module
When you apply the patch and click the "permissions" link in the row of a module, it takes you to the permissions page all right. But the anchor position it jumps to is incorrect.

e.g. jumping to "comments" comes out like this:

This hides a part of the table, correct output would be like this:

The part it hides is exacly the height of the Admin header. So what has to be done is to make Drupal respect the height of the Admin header when jumping to an achor somewhere in the admin section.