[ticket/12415] Use private message instead of "pm" accronym

https://tracker.phpbb.com/browse/PHPBB3-12415

PHPBB3-12415
[ticket/12499] Incorrect call to phpbb\log\log::add() in db:migrate

https://tracker.phpbb.com/browse/PHPBB3-12499

PHPBB3-12499
Merge pull request #2407 from Nicofuma/ticket/12499

[ticket/12499] Incorrect call to phpbb\log\log::add() in db:migrate

* Nicofuma/ticket/12499:
  [ticket/12499] Incorrect call to phpbb\log\log::add() in db:migrate
Merge remote-tracking branch 'MGaetan89/ticket/12415' into develop-ascraeus

* MGaetan89/ticket/12415:
  [ticket/12415] Use private message instead of "pm" accronym
[ticket/12491] Fix clashing USERNAME_FULL template variable.

The user notes and user warn pages have a variable with the same name.

PHPBB3-12491
Merge pull request #2409 from prototech/ticket/12491

[ticket/12491] Fix clashing USERNAME_FULL template variable.

* prototech/ticket/12491:
  [ticket/12491] Fix clashing USERNAME_FULL template variable.