code: public void addFieldLine(String className, String fieldName, SourceLineRange range) {
          fieldLineMap.put(new FieldDescriptor(className, fieldName), range);
      }
docs: Add a line number entry for a field.
  
  @param className
  name of class containing the field
  @param fieldName
  name of field
  @param range
  the line number(s) of the field