tasks 7009: add some documentation

This is part of story #6301: reply to a follow-up comment by email

Change-Id: I9885e4e04b3f48782153848d769e06ab82eae698
Merge commit 'refs/changes/96/2596/3' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  tasks 7009: add some documentation

Change-Id: I112fbbd64ab8fdb4070f2482c114cb8a2d09e058
This is Tuleap 7.1.99.17

Change-Id: I0d258e98f3113cac29ab2f071540d3f07c14540c