* Added ''permalinks'' to ticket changes, using the same look and feel
as those for Wiki section headings.
Note that those permalinks are now also visible when using IExplorer.
* Added inlined ''Reply'' button for each permanent change;
when ''replying'' to a change, the comment associated to the
replied-to change is simply copied and quoted in the comment
textarea. A subsequent change is then recorded to have been
''in reply to'' the former change, enabling some kind of threading
of the comments.
* A permanent change correspond to a modification of the ticket;
ticket changes due to attachments are qualified as non-permanent changes,
as in the current way things work, this kind of change can come and go
(e.g. when the attachment is replaced or deleted)
* there's a new `comment:` link resolver:
- referring to change `n` in the same ticket: `comment:n`
- referring to change `m` in ticket `xyz`: `comment🎫xyz:`
(similar to the `attachment:` link resolver)
