Instead of mixing two strings into a `GList`, use a `PurpleKeyValuePair`.
Use struct initializers and `G_N_ELEMENTS`.
Rename `lv` to `choices` for clarity.
Change from `PurpleRequestFieldList` to `PurpleRequestFieldChoice` as we don't need multiple selection.
Testing Done:
Opened Finch, opened Preferences, saved them, and exited Finch. Re-opened Prefs and confirmed they were saved and as expected.
Reviewed at https://reviews.imfreedom.org/r/2416/
# UPDATING VERSION NUMBERS FOR RELEASES
#
# The version number is:
# <major>.<minor>.<micro><extra>
#
# micro += 1
#
# If any functions have been added to libpurple, Pidgin, or Finch:
# micro = 0
# minor += 1
#
# If backwards compatibility has been broken in libpurple, Pidgin, or Finch:
# micro = 0
# minor = 0
# major += 1
# purple_soversion += 1
#
# extra should be similar to one of the following: