Bug#885685: raising severity of gtksourceview2 reverse depends

[Jeremy Bicha]

Control: severity -1 serious

The Debian GNOME Team is trying to remove gtksourceview2 from Debian.
Therefore, I am bumping the severity of this bug so that this can be
completed for Buster.

I apologize for not raising the severity sooner. Removal from Buster
is blocked by https://bugs.debian.org/ but it looks like that may be
handled in time for Buster.

Because of the late timing of this RC bug in the Buster cycle, please
let me know if you object to gtksourceview2's removal from Buster.

Thanks,
Jeremy Bicha