Since the title of a merge request can often change, it shouldn't be a
part of the topic that we send the message to. Otherwise things would
get messy and confusing.
But at the same time we don't want to make this mandatory. So we add
a new boolean GET parameter that can toggle whether or not the topic
should include the MR title (`use_merge_request_title`).
Fixes#15951.
Signed-off-by: Hemanth V. Alluri <hdrive1999@gmail.com>
Anders Kaseorg
Hemanth V. Alluri
Tim Abbott
Eeshan Garg
Xavier Cooney