gplugin/gplugin

gi-docgen now errors if your annotations are wrong, so this fixes ours

Testing Done:
Ran the build with docs enabled until it succeeded.

Reviewed at https://reviews.imfreedom.org/r/1131/
The following individuals have contributed to this project.
Ankit Vani <a@nevitus.org>
EionRobb <eion@robbmob.com>
Elliott Sales de Andrade <quantum.analyst@gmail.com>
Gary Kramlich <grim@reaperworld.com>
Jason Scherer <schereja@gmail.com>
John Bailey <rekkanoryo@rekkanoryo.org>
Mike Ruprecht <cmaiku@gmail.com>
Olaf Hering <olaf@aepfle.de>
Paul Jimenez <pj@place.org>
Richard Laager <rlaager@pidgin.im>
Sorvival <sorvival@tutanota.com>
ivanhoe <ivanhoe@fiscari.de>