Your PR does multiple things. You may want one PR per “thing”. A thing might be making one type of change across multiple exercises, like syncing them from the problem spec, enabling missing tests or making the syntax consistent. Or it might be adding new tests. But please don’t add new test cases to multiple exercises in the same PR. New test cases should be discussed on a per exercise basis.
As was mentioned on the PR, test cases are synced from the problem spec. Please read Suggesting Exercise Improvements | Exercism's Docs prior to suggesting new test cases. If you still think new tests are warranted, please explain what tests are needed and why they are needed.
As mentioned on the PR, Exercism uses TDD. Additional examples are provided via the tests and not via the description.
The exercises, by and large, are synced from the problem specs and should not be changed from the spec. Is there anything specific that is problematic and in need of fixing? What problem are you trying to solve? The exercises shouldn’t be changed just to change them.