[ENHANCEMENT] <description> Sudoku Possible Numbers for Cell creates more branches than necessary sometimes

[NordLee]

Describe the current behavior of what you're trying to improve. If your enhancement request related to a problem, please also describe the problem.

If a number already exists in the row, column, or region that the rule is being applied to we do not need to create a branch for the number.

Describe the improvement you'd like

For example in the very top left cell we do not need to generate 9 branches for number 1-9. We can instead just generate 2 branches as there are only 2 unknown numbers in the region.

Describe alternatives you've considered

No response

Additional Context

No response

[AndrewAirasian]

This may be a non-issue.

When you use the Possible Cells for Number case rules, the number of branches created is equal to the number of currently empty cells in that group. Even if you select a number that is already given for that group, it will still create that number of branches.

If this issue were to be resolved as described here, it wouldn't make sense not to change the other Sudoku case rules in a similar way, which would probably involve the case rule creating zero branches if a number is given for a certain region (that might confuse the user).

Also, creating all nine branches prompts the user put a contradiction rule for the ones that don't work which, while tedious, is arguably more conducive to sharpening the user's logic skills.