docs: Remove protected symbols from the documentation
docs: Remove protected symbols from the documentation

Folks isn’t really extensible outside its own source tree, so why clutter
up the documentation (and its build process/logs) with protected symbols?

renatofilho/folks2,GNOME/folks,renatofilho/folks,pwithnall/folks,GNOME/folks,renatofilho/folks,pwithnall/folks,renatofilho/folks2,pwithnall/folks,renatofilho/folks,GNOME/folks,renatofilho/folks2,renatofilho/folks,renatofilho/folks2