Add support for custom providers for braille display auto detection

[LeonarddeR]

Link to issue number:

Related to #3564, #2315

Summary of the issue:

Currently, USB and Bluetooth devices are supported for braille display detection. Other devices using other protocols or software devices aren't supported. This pr intends to add support for this.

Description of user facing changes

Noone. User shouldn't experience anything different for now.

Description of development approach

1. Added Chain, a new extension point type that allows to register handlers that return iterables (mainly generators). Calling iter on the Chain returns a generator that iterates over all the handlers.
2. The braille display detector now relies on a new Chain. By default, functions are registered to the chain that yield usb and bluetooth devices. A custom provider can yield own driver names and device matches that are supported by that particular driver. A potential use case would be implementing automatic detection for displays using BRLTTY, for example. It will also be used to fix Braille does not work on secure Windows screens while normal copy of NVDA is running #2315 (see below)
3. Added a moveToEnd method on HandlerRegistrar, which allows changing the order of registered handlers. This allows add-ons to give priority to their handlers, which is especially helpful for both Chain and Filter. NVDA Remote should come for the braille viewer, otherwise controlling a system with braille viewer on with a 80 cell display connected to the controller would lower the display size to 40 unnecessarily. This will also be used to register a custom handler to bdDetect.scanForDevices to support auto detection of the user display on the secure screen instance of NVDA, which should come before USB and Bluetooth.
4. As a bonus, added type hints to extension points. For Filters and Chains, you could provide the value type and then a type checker can check validity.
5. As another bonus, all features are covered by new tests. So there are tests for the Chain extension point and for the specific use case in bdDetect

Testing strategy:

As this touches braille display auto detection quite a lot, probably merge this early in the 2023.2 cycle.

Known issues with pull request:

bdDetect.Detector does no longer take constructor parameters, rather queueBgScan should be called explicitly. This is because if we queue a scan in the constructor of Detector, the detector could switch to a display and disable detection before the _detector was set on the braille handler. Ideally we should use a lock as well, but that might be something as a follow up for both this pr and #14524. Note that though we're changing the constructor of a public class in bdDetect, the doc string of the class explicitly states that the Detector class should be used by the braille module only. That should be enough warning for users not to use this class and therefore I don't consider this API breaking.

Change log entries:

For Developers

• Added a new extension point type called Chain, which can be used to iterate over iterables returned by registered handlers.
• Added the bdDetect.scanForDevices extension point. Handlers can be registered that yield BrailleDisplayDriver/DeviceMatch pairs that don't fit in existing categories, like USB or Bluetooth.

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• Security precautions taken.

[AppVeyorBot]

• PASS: Translation comments check.
• PASS: Unit tests.
• PASS: Lint check.
• FAIL: System tests (tags: installer NVDA). See test results for more information.
• Build (for testing PR): https://ci.appveyor.com/api/buildjobs/djkfnqb95vgfbb10/artifacts/output/nvda_snapshot_pr14531-27495,f748e46b.exe
• CI timing (mins):
  INIT 0.0,
  INSTALL_START 0.8,
  INSTALL_END 0.9,
  BUILD_START 0.0,
  BUILD_END 23.0,
  TESTSETUP_START 0.0,
  TESTSETUP_END 0.3,
  TEST_START 0.0,
  TEST_END 20.0,
  FINISH_END 0.1

See test results for failed build of commit f748e46ba0

[AppVeyorBot]

• PASS: Translation comments check.
• PASS: Unit tests.
• PASS: Lint check.
• FAIL: System tests (tags: installer NVDA). See test results for more information.
• Build (for testing PR): https://ci.appveyor.com/api/buildjobs/oc31b3yfua4npxld/artifacts/output/nvda_snapshot_pr14531-27500,52662b1e.exe
• CI timing (mins):
  INIT 0.0,
  INSTALL_START 0.8,
  INSTALL_END 0.9,
  BUILD_START 0.0,
  BUILD_END 22.7,
  TESTSETUP_START 0.0,
  TESTSETUP_END 0.3,
  TEST_START 0.0,
  TEST_END 20.3,
  FINISH_END 0.1

See test results for failed build of commit 52662b1e0c

[LeonarddeR]

I'm pretty sure all these tests failures are unrelated.

[AppVeyorBot]

• PASS: Translation comments check.
• PASS: Unit tests.
• FAIL: Lint check. See test results for more information.
• FAIL: System tests (tags: installer NVDA). See test results for more information.
• Build (for testing PR): https://ci.appveyor.com/api/buildjobs/rrfo82tuqsnjx27c/artifacts/output/nvda_snapshot_pr14531-27501,7a36ab51.exe
• CI timing (mins):
  INIT 0.0,
  INSTALL_START 0.8,
  INSTALL_END 0.9,
  BUILD_START 0.0,
  BUILD_END 22.5,
  TESTSETUP_START 0.0,
  TESTSETUP_END 0.3,
  TEST_START 0.0,
  TEST_END 22.3,
  FINISH_END 0.1

See test results for failed build of commit 7a36ab513c

[seanbudd]

this type also might be worth turning into a named variable, as it is used repeatedly

[LeonarddeR]

Same issue as abbove, nesting TypeVars in variables doesn't seem to be respected by PyRight.

[seanbudd]

@LeonarddeR can you address merge conflicts now that #14524 is merged

[LeonarddeR]

@LeonarddeR can you address merge conflicts now that #14524 is merged

Done.

[AppVeyorBot]

• PASS: Translation comments check.
• PASS: Unit tests.
• PASS: Lint check.
• FAIL: System tests (tags: installer NVDA). See test results for more information.
• Build (for testing PR): https://ci.appveyor.com/api/buildjobs/2280awctno7fn7x4/artifacts/output/nvda_snapshot_pr14531-27695,35813eaf.exe
• CI timing (mins):
  INIT 0.0,
  INSTALL_START 0.8,
  INSTALL_END 0.8,
  BUILD_START 0.0,
  BUILD_END 23.2,
  TESTSETUP_START 0.0,
  TESTSETUP_END 0.3,
  TEST_START 0.0,
  TEST_END 23.0,
  FINISH_END 0.2

See test results for failed build of commit 35813eaf81