[orx-image-fit] Tweak demo comments

orx-image-fit/src/jvmDemo/kotlin/DemoImageFitSub01.kt

@@ -6,6 +6,17 @@ import org.openrndr.extra.noise.shapes.uniformSub
 import org.openrndr.extra.shapes.primitives.grid
 import kotlin.random.Random
 
+/**
+ * Demonstrates the `imageFitSub()` method, which allows specifying not only a target `Rectangle`,
+ * but also a source `Rectangle`, which is used to set the area of the original image we want to fit
+ * into the target.
+ *
+ * The program also demonstrates the `Rectangle.uniformSub` method, which returns a random sub-rectangle
+ * taking into consideration the minimum and maximum width and height arguments.
+ *
+ * Notice the trick used to generate unique random results changing only once per second by using
+ * the current seconds as an integer seed.
+ */
 fun main() = application {
     configure {
         width = 720