[ticket/12060] Copy this_u_action back to original this->u_action var

PHPBB3-12060
[ticket/12060] Adjust last item in array to use a comma instead of closing parenthesis

PHPBB3-12060
[ticket/12060] Add $update_this_message var to the core event

PHPBB3-12060
[ticket/12060] Remove re-tabbing of html from subsilver2 files

PHPBB3-12060