replace include guards with pragma once

src/graphics/core/Shader.hpp

@@ -1,5 +1,4 @@
-#ifndef GRAPHICS_CORE_SHADER_HPP_
-#define GRAPHICS_CORE_SHADER_HPP_
+#pragma once
 
 #include "typedefs.hpp"
 
@@ -44,5 +43,3 @@ public:
         const std::string& fragmentSource
     );
 };
-
-#endif // GRAPHICS_SHADER_HPP_