Put comments into example scripts.

scripts/speed_test.rhai

@@ -1,5 +1,12 @@
-let x = 1000000;
+// This script runs 1 million iterations
+// to test the speed of the scripting engine.
+
+let x = 1_000_000;
+
+print("Ready... Go!");
+
 while x > 0 {
     x = x - 1;
 }
-print(x);
+
+print("Finished.");