templates: display "(no subject)" when subject is empty

An empty subject, especially in a thread makes it for a slightly jarring
layout. Add a new option empty-subject option to UI with "(no subject")
as the default value. If the subject is empty and the current message is
not the same subject as it's parent in a thread make {{.Subject}}
evaluate to this option's value.

Changelog-added: The `{{.Subject}}` template is evaluated to the new
 option `[ui].empty-subject` if the subject is empty.
Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com>
Acked-by: Robin Jarry <robin@jarry.cc>

0 files changed, 0 insertions, 0 deletions