[ticket/12500] Set a title attribute in user.img()

PHPBB3-12500
[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
[ticket/12402] CAPTCHA plugin migration fails to detect missing plugins

PHPBB3-12402
Merge pull request #2418 from Nicofuma/ticket/12402

[ticket/12402] CAPTCHA plugin migration fails to detect missing plugins

* Nicofuma/ticket/12402:
  [ticket/12402] CAPTCHA plugin migration fails to detect missing plugins
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
Merge pull request #2408 from prototech/ticket/12500

[ticket/12500] Set a title attribute in user.img()

* prototech/ticket/12500:
  [ticket/12500] Set a title attribute in user.img()
Merge remote-tracking branch 'phpbb-core/develop-ascraeus'

* phpbb-core/develop-ascraeus:
  [ticket/12402] CAPTCHA plugin migration fails to detect missing plugins
  [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
  [ticket/12500] Set a title attribute in user.img()