[ticket/11461] Add template event in the footer of view topic pages

PHPBB3-11461
[ticket/11461] Add viewtopic_body_footer_before to the event docs

PHPBB3-11461
[ticket/11461] Further clarify doc for viewtopic_body_footer_before

PHPBB3-11461
[ticket/11461] cut doc entry to 79 cols

PHPBB3-11461
Merge pull request #1311 from VSEphpbb/ticket/11461

[ticket/11461] - Template Event added to bottom of view topic pages