MAINTAINERS: clarify the expected format in the document header

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Patch/commit split by commiter
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Add a maintainer for the delogo filter

I volunteer to maintain the delogo filter for at least the year to
come.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
patch/commit split by commiter
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>