Ensure states/roles are unique (PR #13414)
Values in the State/Role enums are getting large, it is easy for a developer to accidentally duplicate a value.
NVDA states were initially defined as powers of 2 so that the states property on NVDAObject could return multiple (bit flag) values within an integer. However, for a long time now, the states property returns a Python set. The values no longer have to set a unique bit.
Also, now that Role/State constants are enums, we no longer depend on manually
matching values printed in logging with the values in the file (because
enums are named).
Change:
- Decorate Role/State enum classes with unique.
- Prevent errors manually assigning a value by using auto.
