Integrate the new types in this commit into pyGHDL, which it depends on. Record subtypes should have their constraits parsed now, like so, (output from dom.py pretty):

Architectures (1):
  - Name: rtl
    File: regoop_reg.vhd
    Position: 33:13
    Documentation:
    Entity: regoop_reg
    Declared:
      - constant lefty : natural := 10
      - constant righty : natural := 0
      - signal regtest : reg_state_t(lefty? downto righty?)
      - signal regdata : reg_state_t(BIT_FIELDS'range?) := get_reg_initial_value(BIT_FIELDS?, RESET_VALUE?)?

I was not sure how to use RecordConstraint and ArrayConstraint, since the constraints could be Symbol -> Expression?

This is my first PR, it is possible I have committed some devops embarrassments. In particular I did my work on master and only now realized I was supposed to have created a feature branch first. I used --force-with-lease to replace some commits accidentally containing dot folder detritus. Let me know if any of this needs reconciled.