Improve widget suggestion

**What's wrong?**

Widget suggestion functionality has been behaving very strangely of late. When I drag a line out from Test&Score, the proposal is I connect Nomogram, which should only appear after Logistic Regression or Naive Bayes. And where is Confusion Matrix, the most probable next widget to connect?

**How can we reproduce the problem?**

Fresh Orange, File, T&S, LR, drag a line out from T&S.

**What's your environment?**

- Operating system: OSX
- Orange version: 3.37.dev
- How you installed Orange: pip

No source file or test is named. Reproduce the behavior in Orange 3.37.dev using the stated File, Test & Score, and Logistic Regression workflow, then trace the widget suggestion entry point and its ranking rules. Done means the suggestions from Test & Score include the expected next widgets, especially Confusion Matrix, without incorrectly proposing Nomogram.

Written by the indexing model from the issue text.