added ratings to examples

examples/shaders/shaders_texture_tiling.c

@@ -2,6 +2,8 @@
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 *   raylib [shaders] example - texture tiling
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+*   Example complexity rating: [★★☆☆] 2/4
+*
 *   Example demonstrates how to tile a texture on a 3D model using raylib.
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 *   Example contributed by Luis Almeida (@luis605) and reviewed by Ramon Santamaria (@raysan5)