Add glDeleteProgram call to relevant examples.

src/1.getting_started/2.1.hello_triangle/hello_triangle.cpp

@@ -157,6 +157,7 @@ int main()
     // ------------------------------------------------------------------------
     glDeleteVertexArrays(1, &VAO);
     glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
 
     // glfw: terminate, clearing all previously allocated GLFW resources.
     // ------------------------------------------------------------------

src/1.getting_started/2.3.hello_triangle_exercise1/hello_triangle_exercise1.cpp

@@ -163,6 +163,7 @@ int main()
     // ------------------------------------------------------------------------
     glDeleteVertexArrays(1, &VAO);
     glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
 
     // glfw: terminate, clearing all previously allocated GLFW resources.
     // ------------------------------------------------------------------

src/1.getting_started/2.5.hello_triangle_exercise3/hello_triangle_exercise3.cpp

@@ -158,6 +158,8 @@ int main()
     // ------------------------------------------------------------------------
     glDeleteVertexArrays(2, VAOs);
     glDeleteBuffers(2, VBOs);
+    glDeleteProgram(shaderProgramOrange);
+    glDeleteProgram(shaderProgramYellow);
 
     // glfw: terminate, clearing all previously allocated GLFW resources.
     // ------------------------------------------------------------------

src/1.getting_started/3.1.shaders_uniform/shaders_uniform.cpp

@@ -164,6 +164,7 @@ int main()
     // ------------------------------------------------------------------------
     glDeleteVertexArrays(1, &VAO);
     glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
 
     // glfw: terminate, clearing all previously allocated GLFW resources.
     // ------------------------------------------------------------------

src/1.getting_started/3.2.shaders_interpolation/shaders_interpolation.cpp

@@ -161,6 +161,7 @@ int main()
     // ------------------------------------------------------------------------
     glDeleteVertexArrays(1, &VAO);
     glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
 
     // glfw: terminate, clearing all previously allocated GLFW resources.
     // ------------------------------------------------------------------

src/7.in_practice/3.2d_game/0.full_source/program.cpp

@@ -105,7 +105,7 @@ int main(int argc, char *argv[])
 
 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
 {
-    // When a user presses the escape key, we set the WindowShouldClose property to true, closing the application
+    // when a user presses the escape key, we set the WindowShouldClose property to true, closing the application
     if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
         glfwSetWindowShouldClose(window, true);
     if (key >= 0 && key < 1024)

src/7.in_practice/3.2d_game/0.full_source/progress/2.program.cpp

@@ -105,7 +105,7 @@ int main(int argc, char *argv[])
 
 void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
 {
-    // When a user presses the escape key, we set the WindowShouldClose property to true, closing the application
+    // when a user presses the escape key, we set the WindowShouldClose property to true, closing the application
     if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
         glfwSetWindowShouldClose(window, true);
     if (key >= 0 && key < 1024)