Update triangle validity condition in instructions

Clarified the condition for triangle validity by specifying that the sum of the lengths of any two sides must be strictly greater than the length of the third side.

Author: rishabkgautam

exercises/practice/triangle/.docs/instructions.md

@@ -11,7 +11,7 @@ A _scalene_ triangle has all sides of different lengths.
 
 ## Note
 
-For a shape to be a triangle at all, all sides have to be of length > 0, and the sum of the lengths of any two sides must be greater than or equal to the length of the third side.
+For a shape to be a triangle at all, all sides have to be of length > 0, and the sum of the lengths of any two sides must be strictly greater than the length of the third side.
 
 ~~~~exercism/note
 _Degenerate triangles_ are triangles where the sum of the length of two sides is **equal** to the length of the third side, e.g. `1, 1, 2`.