Update current.cursor references to current[cursorStateField]?

[Miles Ingram]

Not sure if this was intended, but since the cursorStateField is customizable I figured the references to current.cursor should be changed to current[cursorStateField]. I may not understand the code fully though so apologies if this is there for a reason.

y-prosemirror/src/plugins/cursor-plugin.js

Lines 127 to 132 in 984175f

   if (current.cursor == null || !Y.compareRelativePositions(Y.createRelativePositionFromJSON(current.cursor.anchor), anchor) || !Y.compareRelativePositions(Y.createRelativePositionFromJSON(current.cursor.head), head)) { 
     awareness.setLocalStateField(cursorStateField, { 
       anchor, head 
     }) 
   } 
 } else if (current.cursor != null && relativePositionToAbsolutePosition(ystate.doc, ystate.type, Y.createRelativePositionFromJSON(current.cursor.anchor), ystate.binding.mapping) !== null) { 

[Dov Alperin]

This is fixed by #88