examples/renderer/03-lines: Make this less obnoxious to look at.

examples/renderer/03-lines/README.txt

@@ -1,3 +1,3 @@
-This example creates an SDL window and renderer, and then draws a giant
-pile of lines, in random colors, every frame.
+This example creates an SDL window and renderer, and then draws a something
+roughly like a Christmas tree with nothing but lines, every frame.