[ticket/11639] generate_text_for_display on functions_posting.php

sub-task of ticket PHPBB3-11635:
find and fix all bypasses of generate_text_for_*

PHPBB3-11639
[ticket/11639] Added an useful comment.

sub-task of ticket PHPBB3-11635:
find and fix all bypasses of generate_text_for_*

PHPBB3-11639
[ticket/11639] Whitespace fixing

sub-task of ticket PHPBB3-11635:
find and fix all bypasses of generate_text_for_*

PHPBB3-11639
Merge remote-tracking branch 'brunoais/ticket/11639' into develop

* brunoais/ticket/11639:
  [ticket/11639] Whitespace fixing
  [ticket/11639] Added an useful comment.
  [ticket/11639] generate_text_for_display on functions_posting.php