[ticket/12272] Fix hardcoded colons in subforums.

In subforums list, under the parent forum description, there are two
harcoded colons instead of {L_COLON}.

PHPBB3-12272
[ticket/12272] Fix hardcoded colons in subforums.

In subforums list, under the parent forum description, there are two
harcoded colons instead of {L_COLON}.

PHPBB3-12272
Merge remote-tracking branch 'maelsoucaze/develop' into develop

* maelsoucaze/develop:
  [ticket/12272] Fix hardcoded colons in subforums.
  [ticket/12272] Fix hardcoded colons in subforums.