Use EditTextInfo for RichEdit50 controls

[seanbudd]

Opening draft PR to start build

Link to issue number:

Fixes #13420, #13927

Summary of the issue:

TODO

Description of user facing changes

Review cursor and system cursor tracking fixed for RichEdit50 controls (e.g. NVDA log viewer, Bookworm).

Description of development approach

Use EditTextInfo for RichEdit50 controls.

Testing strategy:

TODO

Known issues with pull request:

Bookworm sayAll stops after each page. This is different behaviour to 2022.2, where sayAll continues on the new page.
This is better than the current behaviour on master, which causes sayAll to be caught in an infinite loop scrolling at the bottom of the last page.

Change log entries:

Bug fixes

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

[LeonarddeR]

Please note that Wordpad also has a RichEdit50 and there, it works just fine. That made me think that it is just the ITextDocument implementation in WX that's broken. On the contrary, the UIA implementation works properly, I wonder what that uses under the hood.
Anyhow, I think this pr should be limited to WX windows only, i.e. there should be a wx window class on one of the parent windows.

[lukaszgo1]

I'm not sure this PR is a right approach:

• While NVDA can't make system cursor and review cursor follow by using say all in WX's rich text box, Take NVDA log viewer and bookworm as examples #13420 is problematic the main issue we should be trying to solve is Say all does not turn the page properly in bookworm #13927 and that almost certainly don't require such drastic change as this - it regressed in Introducing table sayall commands #13670 and the issue is somewhere in sayAllHandler.
• As mentioned by Leonard we would break all non WX applications using RichEdit50 i.e. Wordpad.
• Even for WX rich edit controls this causes regressions - links cannot be detected and automatic language detection is broken.

In short it seems more reasonable to fix the regression from #13670 for 2022.3, and then try to identify what goes wrong when setting caret in WX RichEdit - perhaps it would be possible to use method for setting caret from non richedit controls and keep the rest of the support from richedit.