ModernCommentsSection

 adds "Table of" before the word "Contents" so that the ToC says "Table of Contents" instead of "Contents".

Features

 * New comments style: The comments had an old, speech bubble style, which turned into a more modern version. The reply button and the edit, delete and history icons turned into the speech bubble icon, the pencil icon, the trash icon and the eye icon, respectively. The avatars are now rounded, as well.
 * New look for the mini editor: The buttons now follow the WDS style, the input area turned into a simple border and the old icons were replaced by bigger, WDS icons.
 * New look for the pagination: See CommentsPagination.
 * New look for the comments header: See ConsistentCommentsHeader.
 * Previewing comments: See CommentPreview.
 * Bonus: The Related Discussions module is also modernized.