mx-path-bar: update documentation
mx-path-bar: update documentation

Add more documentation for various functions

jonnylamb/mx,clutter-project/mx,clutter-project/mx,pwithnall/mx,jonnylamb/mx,jonnylamb/mx,pwithnall/mx,clutter-project/mx,pwithnall/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx