examples/renderer/03-lines: Fix incorrect angle calculation rendering circle.

This fix was contributed by GitHub user hushangazar (thanks!).

Closes #14599.

examples/renderer/03-lines/lines.c

@@ -77,8 +77,9 @@ SDL_AppResult SDL_AppIterate(void *appstate)
         const float size = 30.0f;
         const float x = 320.0f;
         const float y = 95.0f - (size / 2.0f);
+        const float r = (float) ((double)i * (SDL_PI_F / 180.0));
         SDL_SetRenderDrawColor(renderer, SDL_rand(256), SDL_rand(256), SDL_rand(256), SDL_ALPHA_OPAQUE);
-        SDL_RenderLine(renderer, x, y, x + SDL_sinf((float) i) * size, y + SDL_cosf((float) i) * size);
+        SDL_RenderLine(renderer, x, y, x + SDL_cosf(r) * size, y + SDL_sinf(r) * size);
     }
 
     SDL_RenderPresent(renderer);  /* put it all on the screen! */