Update the code in 01-05

Replace 'GLchar' with 'char' to be consistent with the original English article.

docs/01 Getting started/05 Shaders.md

@@ -323,7 +323,7 @@ public:
     unsigned int ID;
   
     // 构造器读取并构建着色器
-    Shader(const GLchar* vertexPath, const GLchar* fragmentPath);
+    Shader(const char* vertexPath, const char* fragmentPath);
     // 使用/激活程序
     void use();
     // uniform工具函数