SDL: examples/renderer/03-lines: use a gray background.

SDL Commits
1 
From 2e3e5abd7d49fd21b558553c773a016972412c48 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Thu, 19 Sep 2024 12:58:13 -0400
Subject: [PATCH] examples/renderer/03-lines: use a gray background.

---
 examples/renderer/03-lines/renderer-lines.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/renderer/03-lines/renderer-lines.c b/examples/renderer/03-lines/renderer-lines.c
index 66f65af0b3104..a2c95396036bb 100644
--- a/examples/renderer/03-lines/renderer-lines.c
+++ b/examples/renderer/03-lines/renderer-lines.c
@@ -56,7 +56,7 @@ SDL_AppResult SDL_AppIterate(void *appstate)
     };
 
     /* as you can see from this, rendering draws over whatever was drawn before it. */
-    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);  /* black, full alpha */
+    SDL_SetRenderDrawColor(renderer, 100, 100, 100, 255);  /* black, full alpha */
     SDL_RenderClear(renderer);  /* start with a blank canvas. */
 
     /* You can draw lines, one at a time, like these brown ones... */