D6824: notify: add option for deterministic message-id generation

[Joerg Sonnenberger]

On Sat, Sep 07, 2019 at 11:40:44AM +0000, joerg.sonnenberger (Joerg Sonnenberger) wrote:
> REVISION DETAIL
>   https://phab.mercurial-scm.org/D6824

Pierre-Yves asked offline why I asked a new option for this and why it
is not the default. Message-Id is supposed to be unique world-wide and
while it is desirable to have a deterministic mechanism for them for
creating follow-up emails, it needs organisational control for ensuring
the uniqueness.

Joerg