Consider formatting conflicting issues list with one item per row

[tidoust]

When doing references, GitHub visually expands a reference issue when it is on its own line, but it doesn't when the reference appears inline. So, a list of conflicts written as #42, #18, #76 will appear as such, whereas:

- #42
- #18
- #76

... will be rendered with issue titles. The expanded version is more visually appealing as it allows to quickly grasp what other issues the issue is conflicting with. The bot understands both formats but currently forces a CSV format. It could rather force the use of a real list.

[tidoust]

Similarly, some proposers prefer to put full names of additional session chairs, wrapped in a link to the user's page on GitHub. Code could process that URL to extract the GitHub handle instead of rejecting that format.