Identifiers in enum class can overlap.

Reverting Capitalization of Red/Purple/Blue in enum class example.

CppCoreGuidelines.md

@@ -6252,7 +6252,7 @@ Instead use an `enum class`:
     void PrintColor(int color);
 
     enum class Webcolor { red=0xFF0000, green=0x00FF00, blue=0x0000FF };
-    enum class Productinfo { Red=0, Purple=1, Blue=2 };
+    enum class Productinfo { red=0, purple=1, blue=2 };
 
     Webcolor webby = Webcolor::blue;
     PrintColor(webby);  // Error: cannot convert Webcolor to int.