1.85.0 regressed our C/C++ extension's edtior.wordBasedSuggestions set in "configurationDefaults" and no migration is applied

[sean-mcmanus]

Does this issue occur when all extensions are disabled?: N/A (requires an extension).

• VS Code Version: 1.85.0
• OS Version: Any

Steps to Reproduce:

1. Use our C/C++ extension or see the PR at https://github.com/microsoft/vscode-cpptools/pull/11773/files
2. Type "namespace f" in a .cpp file and see that the editor.wordBasedSuggestion false is not being applied (it worked in 1.84.0).

Expected: There should be some automatic "migration" code that is automatically applied to extension's settings like is done for user-set settings.

The change was caused by #197690 .

[hediet]

@alexr00 do you know if sth changed here?

[alexr00]

C++ grammar has been frozen for a while.

@sean-mcmanus thanks for including your root causing to #197690!