Add caveats to h3Line description
@@ -594,6 +594,15 @@ static void cubeRound(float i, float j, float k, CoordIJK* ijk) {
* example if they are very far apart. It may also fail when finding
* distances for indexes on opposite sides of a pentagon.
*
+ * Notes:
+ *
+ * - The specific output of this function should not be considered stable
+ * across library versions. The only guarantees the library provides are
+ * that the line length will be `h3Distance(start, end) + 1` and that
+ * every index in the line will be a neighbor of the preceding index.
+ * - Lines are drawn in grid space, and may not correspond exactly to either
+ * Cartesian lines or great arcs.
+ *
* @param start Start index of the line
* @param end End index of the line
* @param out Output array, which must be of size h3LineSize(start, end)
