triangle: note is incorrect

[Anton-4]

A note was recently added to the triangle description in #2579:

We opted to not include tests for degenerate triangles (triangles that violate these rules) to keep things simpler.
You may handle those situations if you wish to do so, or safely ignore them.

But there are still test cases that violate these rules:

(0, 0, 0)
(1, 1, 3)
(1, 3, 1)
(3, 1, 1)
(7, 3, 2)

This can be confusing to those trying to solve the problem.

[IsaacG]

1. Please use the forum to discuss problem spec issues.
2. Other than possible (0, 0, 0), none of these are degenerate triangles.