Add language tags for C code sections

docs/quick.dox

@@ -21,7 +21,7 @@ behave differently in GLFW 3.
 In the source files of your application where you use GLFW, you need to include
 its header file.
 
-@code
+@code{.c}
 #include <GLFW/glfw3.h>
 @endcode
 
@@ -38,7 +38,7 @@ This example uses files generated by [glad](https://gen.glad.sh/).  The GLFW
 header can detect most such headers if they are included first and will then not
 include the one from your development environment.
 
-@code
+@code{.c}
 #include <glad/gl.h>
 #include <GLFW/glfw3.h>
 @endcode
@@ -48,7 +48,7 @@ GLFW_INCLUDE_NONE before the GLFW header to explicitly disable inclusion of the
 development environment header.  This also allows the two headers to be included
 in any order.
 
-@code
+@code{.c}
 #define GLFW_INCLUDE_NONE
 #include <GLFW/glfw3.h>
 #include <glad/gl.h>
@@ -61,7 +61,7 @@ Before you can use most GLFW functions, the library must be initialized.  On
 successful initialization, `GLFW_TRUE` is returned.  If an error occurred,
 `GLFW_FALSE` is returned.
 
-@code
+@code{.c}
 if (!glfwInit())
 {
     // Initialization failed
@@ -73,7 +73,7 @@ Note that `GLFW_TRUE` and `GLFW_FALSE` are and will always be one and zero.
 When you are done using GLFW, typically just before the application exits, you
 need to terminate GLFW.
 
-@code
+@code{.c}
 glfwTerminate();
 @endcode
 
@@ -92,7 +92,7 @@ In case a GLFW function fails, an error is reported to the GLFW error callback.
 You can receive these reports with an error callback.  This function must have
 the signature below but may do anything permitted in other callbacks.
 
-@code
+@code{.c}
 void error_callback(int error, const char* description)
 {
     fprintf(stderr, "Error: %s\n", description);
@@ -104,7 +104,7 @@ the error callback is one of the few GLFW functions that may be called before
 initialization, which lets you be notified of errors both during and after
 initialization.
 
-@code
+@code{.c}
 glfwSetErrorCallback(error_callback);
 @endcode
 
@@ -115,7 +115,7 @@ The window and its OpenGL context are created with a single call to @ref
 glfwCreateWindow, which returns a handle to the created combined window and
 context object
 
-@code
+@code{.c}
 GLFWwindow* window = glfwCreateWindow(640, 480, "My Title", NULL, NULL);
 if (!window)
 {
@@ -138,7 +138,7 @@ You can select the OpenGL profile by setting the `GLFW_OPENGL_PROFILE` hint.
 This program uses the core profile as that is the only profile macOS supports
 for OpenGL 3.x and 4.x.
 
-@code
+@code{.c}
 glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
 glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
@@ -151,7 +151,7 @@ if (!window)
 
 When a window and context is no longer needed, destroy it.
 
-@code
+@code{.c}
 glfwDestroyWindow(window);
 @endcode
 
@@ -163,7 +163,7 @@ and its handle becomes invalid.
 
 Before you can use the OpenGL API, you must have a current OpenGL context.
 
-@code
+@code{.c}
 glfwMakeContextCurrent(window);
 @endcode
 
@@ -176,7 +176,7 @@ a current context to load from.  This example uses
 [glad](https://github.com/Dav1dde/glad), but the same rule applies to all such
 libraries.
 
-@code
+@code{.c}
 gladLoadGL(glfwGetProcAddress);
 @endcode
 
@@ -191,7 +191,7 @@ Note that __the window isn't actually closed__, so you are expected to monitor
 this flag and either destroy the window or give some kind of feedback to the
 user.
 
-@code
+@code{.c}
 while (!glfwWindowShouldClose(window))
 {
     // Keep running
@@ -213,7 +213,7 @@ Each window has a large number of callbacks that can be set to receive all the
 various kinds of events.  To receive key press and release events, create a key
 callback function.
 
-@code
+@code{.c}
 static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
     if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
@@ -223,7 +223,7 @@ static void key_callback(GLFWwindow* window, int key, int scancode, int action,
 
 The key callback, like other window related callbacks, are set per-window.
 
-@code
+@code{.c}
 glfwSetKeyCallback(window, key_callback);
 @endcode
 
@@ -237,7 +237,7 @@ Once you have a current OpenGL context, you can use OpenGL normally.  In this
 tutorial, a multicolored rotating triangle will be rendered.  The framebuffer
 size needs to be retrieved for `glViewport`.
 
-@code
+@code{.c}
 int width, height;
 glfwGetFramebufferSize(window, &width, &height);
 glViewport(0, 0, width, height);
@@ -265,7 +265,7 @@ returns the number of seconds since initialization.  The time source used is the
 most accurate on each platform and generally has micro- or nanosecond
 resolution.
 
-@code
+@code{.c}
 double time = glfwGetTime();
 @endcode
 
@@ -279,7 +279,7 @@ the one being displayed and the back buffer the one you render to.
 When the entire frame has been rendered, the buffers need to be swapped with one
 another, so the back buffer becomes the front buffer and vice versa.
 
-@code
+@code{.c}
 glfwSwapBuffers(window);
 @endcode
 
@@ -296,7 +296,7 @@ For these reasons, applications will typically want to set the swap interval to
 one.  It can be set to higher values, but this is usually not recommended,
 because of the input latency it leads to.
 
-@code
+@code{.c}
 glfwSwapInterval(1);
 @endcode
 
@@ -315,7 +315,7 @@ There are two methods for processing pending events; polling and waiting.  This
 example will use event polling, which processes only those events that have
 already been received and then returns immediately.
 
-@code
+@code{.c}
 glfwPollEvents();
 @endcode