[ticket/12440] Set browser URL to point to specific post when using view=unread

PHPBB3-12440
[ticket/12440] Use a more generic approach for replacing the URL.

PHPBB3-12440
Merge pull request #2414 from prototech/ticket/12440

[ticket/12440] Set browser URL to point to specific post when using view=unread

* prototech/ticket/12440:
  [ticket/12440] Use a more generic approach for replacing the URL.
  [ticket/12440] Set browser URL to point to specific post when using view=unread

Conflicts:
	phpBB/styles/prosilver/template/viewtopic_body.html