ShaderTools: err, I suppose there's a reason why the define is here.

To not make Doxygen think this is where all the types are defined.

src/Magnum/ShaderTools/ShaderTools.h

@@ -36,8 +36,8 @@ namespace Magnum { namespace ShaderTools {
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
 class AbstractConverter;
-#endif
 enum class Stage: UnsignedInt;
+#endif
 
 }}