The description of PTROFFSET in the RefGude should be clarified

Summary

The description of PTROFFSET in the RefGude should be clarified

What is the expected correct behavior?

Suggested text:

The value of the pointer field calculated as the difference between beginning of the pointer field and the beginning of the pointed field in bits, minus the ptr offset value, expressed in whole UNIT (which is 8 bit, octet by default). The PTROFFSET is measured in bits.

Titan version

8.3.0

/cc @aknappqwt @mmagyari