This change makes some small polish changes to fix up some issues that I

noticed while testing Kanghee Park's read-only mode changes:

Hide the "Markdown" link in the comment dialog.
Fix the spacing in the comment dialog.
Fix up cursors and interaction for the star and archive functions.
Make it so that the banner is always shown when read-only mode is

  enabled, even for admins that can still interact with everything.

Verified the look and functionality of these changes.