chore(examples): add splash example credit

examples/splash/main.go

@@ -1,5 +1,13 @@
 package main
 
+// An example animation of a rotating color gradient. In addition to being
+// a nice example, it's a good one for testing performance.
+//
+// It's ported from the splash.py example, by the talented Will McGugan, from
+// the excellent Textualize project.
+//
+// https://github.com/Textualize/textual/blob/4ce6b79dea61ca4b1427be85533c0deac3145118/examples/splash.py
+
 import (
 	"fmt"
 	"image/color"