Prevent running Fix-All on-save from removing unused imports #4561

Placeholder for release notes, and for discoverability when this behaviour changes.

Before a recent SDK change, using fix-all-on-save in VS Code would also remove unused imports:

"editor.codeActionsOnSave": {
	"source.fixAll": true
}

This behaviour was a little inconsistent without iterative fix-all (it would not remove the imports if other fixes were applied). Iterative fix-all made it consistent, but this behaviour is not what many users want (for example if they'd temporarily commented out code).

With this change, imports will not be touched when using fix-all if it was invoked automatically by save. However, it's possible to retain the original behaviour by invoked listing the original fix, or (more efficiently) source.organizeImports) to run on-save:

"editor.codeActionsOnSave": {
	"source.fixAll": true,
	"source.organizeImports": true
}