[orx-shapes] Add demo descriptions

orx-shapes/src/jvmDemo/kotlin/ordering/DemoHilbertOrder01.kt

@@ -6,6 +6,17 @@ import org.openrndr.extra.noise.uniform
 import org.openrndr.extra.shapes.ordering.hilbertOrder
 import kotlin.random.Random
 
+/**
+ * Demonstrates the use of the `hilbertOrder` method to sort 2D points in a list of random points.
+ *
+ * When drawing the sorted points as a line strip, this line crosses itself fewer times than if the
+ * points were drawn in a random order (sometimes zero crossings, depending on the number and layout of the points).
+ *
+ * The Hilbert curve (also known as the Hilbert space-filling curve) is a continuous fractal
+ * space-filling curve first described by the German mathematician David Hilbert in 1891
+ * https://en.wikipedia.org/wiki/Hilbert_curve
+ *
+ */
 fun main() = application {
     configure {
         width = 720