Seemingly incorrect `immediate` field name, in JSON document

[64kramsystem]

The JSON document has two immediate fields, one for any given opcode, and the other for the operands.

It seems though, that this field is incorrect. I've had a discussion on Discord with another experienced dev, and he suggested to change the name and value of the field (see discussion).

For example, the unprefixed 0x08 (INC C) is marked as immediate both at the opcode level and at the operand level.