pidgin/pidgin

Add a missing transfer annotation to purple_history_manager_get_active

Testing Done:
Build `libpurple/Purple-3.0.gir` and verified the warning was gone.

Reviewed at https://reviews.imfreedom.org/r/1041/
syntax: glob
.*.swp
.DS_Store
.flatpak-builder
*.pyc
*~
\#*\#
subprojects/*/
syntax: regexp
^build(.+)?\/
win32-install-dir(\.release)?
po\/pidgin\.pot$