pidgin/pidgin

Add documentation for all PURPLE_TYPE_ functions as well as PURPLE_TUNE_ constants

Add document for all PURPLE_TYPE_ defines as well as PURPLE_TUNE_ constants

Testing Done:
Compile and doc build.

Reviewed at https://reviews.imfreedom.org/r/92/
[Desktop Entry]
Name=Pidgin
GenericName=Internet Messenger
Comment=Chat over IM. Supports AIM, Google Talk, Jabber/XMPP, and more
Exec=purple3-url-handler %u
TryExec=purple3-url-handler
Icon=pidgin
StartupNotify=false
Terminal=false
NoDisplay=true
Type=Application
Categories=Network;InstantMessaging;RemoteAccess;ConsoleOnly;
MimeType=x-scheme-handler/aim;x-scheme-handler/gg;x-scheme-handler/icq;x-scheme-handler/irc;x-scheme-handler/msnim;x-scheme-handler/sip;x-scheme-handler/xmpp;x-scheme-handler/ymsgr
@USES_MM_CHAT_SECTION@